I have tried too, in my time, to be a philosopher;

but I don’t know how, cheerfulness was always breaking in.

OLIVER EDWARDS in Boswell’s Life of Samuel Johnson (1791)

History records surprisingly few cheerful people. Philosophers, in particular, have the reputation for being about as miserable as comedians, but Epicurus (341–270 BC) isn’t one of them. His poor reputation is of a very different kind: as the high priest of high living and sensual pleasure, the philosopher of the debauchee and the gourmand.

Except that he wasn’t. Far from indulging in orgies and banquets, Epicurus lived on barley bread and fruit, with cheese as a special treat on only feast days. Celibate himself, he discouraged sexual relations among his followers, and his students were allowed no more than a pint of wine a day.

But Epicurus had the misfortune to live in the highly competitive golden age of Greek philosophy, where he found himself up against the Academy, founded by Plato, and the porch (stoa) of the Stoics—both articulate and well-organized opponents. The mud they slung at him more than two millennia ago has stuck firm.

He was born into an Athenian family but grew up on the island of Samos, a mile off the coast of what is now Turkey. He was thirty-five before he arrived in Athens, taking a house with a large garden and setting up a school. He had brought his pupils with him, and unlike the Academicians and Stoics, with their very public disputations, the Epicureans kept themselves to themselves. Inscribed over the entrance arch were the alluring words: “Stranger, here you will do well to tarry; here our highest good is pleasure.” You can see how the rumors started.

In fact, the Epicurean definition of pleasure is quite precise. It is simply “the absence of pain in the body and of trouble in the soul,” or ataraxia. This tranquil state is to be attained by “sober reasoning” and most specifically not by “an unbroken succession of drinking bouts and of revelry,” “sexual lust,” and “the enjoyment of fish and other delicacies.”

Epicurus’s idea of “the good life” was also not what you’d expect. “It is impossible,” he wrote, “to live a pleasant life without living wisely and honorably and justly, and it is impossible to live wisely and honorably and justly without living pleasantly.” Decent behavior depends on a decent standard of living. Asked to name the bare necessities, most of us would list food, water, warmth, and shelter, but Epicurus insisted on a few more: freedom, thought, and friendship. “Of all the things,” he wrote, “which contribute to a blessed life, none is more important, more fruitful, than friendship.” Food and wine are pleasurable mainly because they are sociable. “Eating or drinking without a friend is the life of a lion or a wolf.”

For a good meal with friends, something you can well do without (“fish and other delicacies” aside) is fear. “It is better to be free of fear while lying upon a pallet, than to have a golden couch and a rich table and be full of trouble.” The German philosopher Friedrich Nietzsche observed: “Wisdom hasn’t come a step further since Epicurus, but has often gone many thousands of steps backward.” One such backward step is to forget Epicurus’s core idea: that freedom from pain depends on the absence of fear—fear of loss, fear of being found out, and worst of all, fear of death. Epicurus solved the last one by dropping the whole idea of an afterlife—and with it the fear of eternal punishment. When you’re gone, you’re gone. What matters is a calm and contented life in the here and now. Ideally, sitting under a tree, talking philosophy with friends. But what Epicurus meant by “philosophy” was different, too. “Vain is the word of a philosopher,” he said, “which does not heal any suffering.”

This cheery benevolence makes Epicurus one of the sanest and most attractive of the major Greek philosophers. But there is much more to him than that. He was the first person to advocate equal rights for slaves and for women, and the first to offer free schooling. In teaching that we should believe only what we can test through observation, he laid the cornerstone of scientific method; and he was also one of the founders of atomic physics. Democritus of Abdera (460–570 BC)—known as the “laughing philosopher” for finding life more comic than tragic—had guessed that the world was composed of atomoi, units of matter that were too small to be divided, but Epicurus took this further: “Events in the world are ultimately based on the motions and interactions of atoms moving in empty space.” That implied no organizing intelligence—any gods were made of atoms like the rest of us. These ideas—of fundamental randomness and the lack of a planned design for nature—anticipate both quantum mechanics and natural selection. Furthermore, Epicurus’s dictum “Minimize harm, maximize happiness” was the first Greek version of the Golden Rule (“Do as you would be done by”). It has inspired thinkers as diverse as Thomas Jefferson (the words “the pursuit of happiness” in the U.S. Constitution are based on it) and Karl Marx (who gained his doctorate from a study of Epicurus). The humanist movement also claims him. The ancient sentence, engraved in Latin on the tombstones of his many Roman followers—non fui, fui, non sum, non curo, “I was not; I have been; I am not; I do not mind”—is often used at humanist funerals. The philosophy of Epicurus is closer to Buddhism than any other Western philosopher’s. Maxims such as “If you will make a man happy, add not to his riches, but take away from his desires” and “A free life cannot acquire many possessions, because this is not easy to do without servility to mobs or monarchs” suggest he may have known of the teachings of Gautama Buddha (about 563–483 BC), who had died more than a century earlier. Equally likely, Epicurus had simply come to the same conclusions from the same close observation of human life and suffering.

We don’t know much about Epicurus the man, perhaps because he advocated the “hidden life”: keeping the company of friends, not getting married, and refusing the limelight that other philosophers craved. But even his opponents praised him for his humane and genial temperament. His three hundred books have survived only as quotations in the work of other writers. All we have by him are three letters. One was written to his friend and pupil Idomeneus as Epicurus was dying, painfully, from kidney stones:

I have written this letter to you on a happy day to me, which is also the last day of my life. For I have been attacked by a painful inability to urinate, and also dysentery, so violent that nothing can be added to the violence of my sufferings. But the cheerfulness of my mind, which comes from the recollection of all my philosophical contemplation, counterbalances all these afflictions. And I beg you to take care of the children of Metrodorus, in a manner worthy of the devotion shown by the young man to me, and to philosophy.

This mix of courage, humor, and concern for others is the real Epicureanism. Weathering the unjust slurs, it became, with Stoicism, the most popular belief system in the classical world for more than eight hundred years, until the adoption of Christianity as the state religion of the Roman Empire in AD 312. You can see why the Church suppressed it. Here is Epicurus’s mantra, known as the Tetrapharmakon, or “Four Cures.”

Don’t fear God,

Don’t worry about death;

What is good is easy to get, and

What is terrible is easy to endure.

It was almost two thousand years before anything this simple and useful was produced again in the West: a kind of How to Be Cheerful in Four Easy Lessons.

Vegetarianism, brotherly love, and kidney stones also figure in the action-packed life of Benjamin Franklin (1706–90), “the only President of the United States who was never President of the United States.”

Of all America’s Founding Fathers, he best represents the excitement, energy, and originality of the new colony. Born in Boston, the fifteenth of seventeen children and the youngest son of a youngest son, his parents were English Puritans. His father, Josiah, was a candle maker who had emigrated from Northampton in 1683. The family wasn’t rich, and Ben left school at ten. By twelve, he was working as a printer, apprenticed to his elder brother James.

In 1721, James had established the New-England Courant, the American colonies’ first independent newspaper. The following year, the paper ran a series of letters purporting to be from a Mrs. Silence Dogood, a middle-aged widow. They caused a small sensation; not only were they a fine political satire, aimed at embarrassing the Puritan establishment in the city, but the character of Mrs. Dogood was so convincing that several gentlemen wrote in with proposals of marriage. When James discovered the letters were in fact the work of his younger brother, he was furious. But the sixteen-year-old Ben, flushed with his first literary success and tired of being bullied by James, responded by doing the unthinkable: He quit his job and ran away, first to New York and then to Philadelphia, where he found work in another printing house.

Mischievousness, courage, and standing up to tyranny were to be the hallmarks of Ben Franklin’s life, finding their ultimate expression in the Declaration of Independence. After an adventurous two-year interlude in London consorting with “lewd women,” impressing the British by swimming in the Thames, and learning the art of typesetting, he returned to Philadelphia, where he set up his own printing firm and founded a society of like-minded tradesmen called the Junto—loosely derived from the Spanish for “joined”—whose innovative thinking was to revolutionize the city.

Philadelphia was already an interesting place. Named after the Greek for “brotherly love,” unlike most of the Puritan enclaves (such as Boston) it embraced religious toleration. All the Protestant denominations were represented—Moravians, Lutherans, Quakers, Calvinists—and there was even a Jewish community. Franklin, though always a believer, was no sectarian. He approved of the idea that all faiths should be allowed to flourish side by side. In a letter justifying his views to his hard-line Puritan parents he explained: “I think vital religion has always suffered when orthodoxy is more regarded than virtue. And the Scripture assures me that at the last day we shall not be examined by what we thought, but what we did.”

As Franklin’s business prospered, he was able to do an astonishing amount. In 1737, at the age of thirty, he was appointed as the city’s postmaster and swiftly transformed the postal service. Along with his colleagues in the Junto, he helped finance America’s first public library, started the first civic fire brigade and fire insurance scheme, opened the first public hospital, improved the city’s street lighting, built pavements, set up a police force, and founded the University of Pennsylvania. Some historians have argued that the close partnership between business, charities, and civic institutions that is still such a feature of American cities today was Franklin’s invention.

It was by no means the only thing he invented. As an eleven-year-old he devised a pair of wooden hand flippers to help him swim faster. They didn’t work particularly well, but he never looked back. He is credited with inventing the lightning conductor; the odometer; the domestic log-burning stove (known still as a Franklin stove today); an extension arm for removing books from high shelves; a twenty-four-hour clock; a phonetic alphabet that did without the letters c, j, q, w, x, and y; a rocking chair with a built-in fan; the eerie-sounding glass armonica (Mozart and Beethoven both composed pieces for it); bifocal lenses (he asked his optician to saw his existing lenses in two, grind the top halves more thinly, and then set all four pieces back in the frame); and the notion of daylight saving time. He also produced the first flexible urinary catheter in America to help alleviate the agony of his brother John, who suffered from kidney stones. Nothing was beneath his curiosity: He once submitted a paper to the Royal Academy in Brussels recommending the search for a drug “that shall render the natural discharges of wind from our bodies as perfume,” believing this would do more for the common good than the works of Descartes, Aristotle, and Newton put together.

He also made important contributions to science—the most famous being his daringly hands-on demonstration that lightning was electrical. This occurred in 1752, when by flying a silken kite in a storm and touching a key tied to the string, he showed that electricity from the sky could be conducted through his body. Fortunately, the tingling sensation he experienced came from the latent charge in the thunderclouds rather than from a lightning strike on the kite. The latter would have resulted in not so much a tingling sensation as a 200-million-volt instant barbecue—as the Swedish physicist Georg Richmann found out less than a year later. In a fatal echo of Franklin’s experiment, Richmann ran a metal wire from the roof of his house in St. Petersburg. The wire ended with an iron bar hanging above a bowl of water filled with iron filings and a magnetic needle. The plan was to cause an electrical spark between the bar and the filings. According to his assistant, what happened to Richmann was much more dramatic. As he watched, he saw “a Globe of blue and whitish Fire, about four inches Diameter, dart from the Bar against M. Richmann’s Forehead, who fell backwards without the least Outcry. This was succeeded by an Explosion like that of a small Cannon.” Richmann was killed instantly (though the lightning left only a small red mark on his forehead); the assistant had his clothes singed and torn by pieces of burning wire; and the door to the room was ripped off its hinges.

Franklin had other, less perilous, insights. He was puzzled by the fact that mail boats leaving Falmouth in Cornwall took two weeks longer to reach New York than merchant ships leaving from London. To solve the mystery, he took the direct approach and invited his cousin Timothy, a Nantucket whaler captain, to supper. Learning about the fierce ocean current that the whalers and the merchants avoided, but that the mail boats regularly sailed into, Franklin commissioned a group of experienced sailors to map the current and gave it a name: the Gulf Stream. This was typical of Franklin: If he didn’t understand something, he studied it carefully and asked his friends for their advice—an approach Epicurus would have applauded. He wasn’t always right—he called the Gulf Stream a river, which it isn’t—but his instincts were sound. In 1756 his scientific achievements received the highest possible accolade when he became one of the very few Americans to be elected to the Royal Society in London.

When he wasn’t inventing things, making money, or pushing back the frontiers of scientific knowledge, Franklin worked as a diplomat, first in London and then Paris, skillfully negotiating America’s case and ultimately getting the newly independent United States recognized by the world’s two superpowers, France and Great Britain. He is the only one of the Founding Fathers to have signed all three of the key documents: the Declaration of Independence, the U.S. Constitution, and the Treaty of Paris that ended the Revolutionary War. His success as both diplomat and businessman was due to the fact that people enjoyed doing business with him. He was charming, witty, and a natural deal maker, always alert to the possibilities of compromise. Crucially, he could laugh at himself, which is one of the reasons his unfinished autobiography is so likable. Describing how, at the age of twenty, he started on “the bold and arduous project of arriving at moral perfection,” he set about it with scientific rigor, drawing up a list of the thirteen virtues he wanted to acquire (with temperance at the top of the list), quickly deciding he couldn’t manage all at once and so deciding to take on one a week. The account of his struggles—particularly his failures (which, with a dry printer’s wit, he calls errata)—is both very funny and very inspiring: The Seven Habits of Highly Effective People with jokes.

Here’s a good story from the book. Franklin had been asked to publish a “scurrilous and defamatory” article in his newspaper, the Pennsylvania Gazette, but he strongly disagreed with both the tone and the content:

To determine whether I should publish it or not, I went home in the evening, purchased a twopenny loaf at the baker’s, and with the water from the pump made my supper; I then wrapped myself up in my great-coat, and laid down on the floor and slept till morning, when, on another loaf and a mug of water, I made my breakfast. From this regimen I feel no inconvenience whatever. Finding I can live in this manner, I have formed a determination never to prostitute my press to the purposes of corruption and abuse of this kind.

It was typical of the man: at once morally admirable, rigorously original, and faintly absurd. And in realizing that he could survive perfectly well living on bread and water and sleeping on the floor, he was a true Epicurean.

But there was to be no “hidden life” for Franklin. In his seventies, as U.S. ambassador to France, though he dressed like a simple backwoodsman in a fur hat and a plain brown suit, there was no escaping the fact he was one of the world’s most famous men. As he wrote to his daughter:

My picture is everywhere, on the lids of snuff boxes, on rings, busts. The numbers sold are incredible. My portrait is a best seller, you have prints, and copies of prints and copies of copies spread everywhere. Your father’s face is now as well known as the man in the moon.

He was also—despite being old, bald, and fat—very popular with the ladies. Although, as a younger man, he did admit to at least one illegitimate child (his son William), he probably wasn’t as much of an old goat as some have painted him. He certainly liked women—and had an uncanny ability to write as though he were one (as his many female pseudonyms show)—though most of his amorous liaisons seem to have been intimate but not sexual friendships, usually with him in the role of mentor. Which isn’t to say he didn’t get up to mischief. At one of the endless parties the French threw for him, a young woman patted his portly belly and remarked, “Dr. Franklin, if this were on a woman, we’d know what to think.” To which he replied, “Half an hour ago, mademoiselle, it was on a woman and now what do you think?” In this vein, when asked by a young male friend for advice in choosing a mistress, Franklin wrote back extolling the virtues of older women. He listed eight good reasons, including:

5. Because … The Face first grows lank and wrinkled; then the Neck; then the Breast and Arms; the lower Parts continuing to the last as plump as ever: So that covering all above with a Basket, and regarding only what is below the Girdle, it is impossible of two Women to know an old from a young one. And as in the dark all Cats are grey, the Pleasure of corporal Enjoyment with an old Woman is at least equal, and frequently superior, every Knack being by Practice capable of Improvement.

His final reason was even more to the point: “They are so grateful!” As always with Franklin, it’s difficult to tell just how serious he was being, but the letter, first discovered in 1881, has done him no harm. In 2003 Time magazine published an article on him titled “Why He Was a Babe Magnet.” Franklin’s more self-deprecating name for himself was “Dr. Fatsides.”

Benjamin Franklin—scientist, diplomat, philosopher, inventor, businessman, civic leader, patriot, humorist, revolutionary, and ladies’ man—died in 1790, aged eighty-four. Sixty years earlier he’d written his own immortal epitaph:

The Body of B. Franklin Printer; Like the Cover of an old Book, Its Contents torn out, And stript of its Lettering and Gilding, Lies here, Food for Worms. But the Work shall not be wholly lost: For it will, as he believ’d, appear once more, In a new & more perfect Edition, Corrected and Amended By the Author.

Half the population of Philadelphia—twenty thousand people—attended his funeral, and his pallbearers included representatives of all the main religious denominations. (Ever the pragmatist, Franklin had been careful to contribute to each of their building funds, including one for a new synagogue.) Few men can honestly say they have left the world a better place. Through the warmth and courage of his character and the deep originality of his mind, Citizen Ben Franklin, the first self-taught American genius, was certainly one of them.

The career of the English doctor Edward Jenner (1749–1823) can’t possibly match Franklin’s for excitement. He spent most of his life working quietly in his home village of Berkeley, in Gloucestershire, but he, too, changed the world beyond all recognition. The two men shared the same sunny outlook and the same voracious enthusiasm for learning and experiment. In Jenner’s case, this led to a discovery that has probably saved more human lives than any other.

The eighth of nine children, he lost both his parents before he was six, but his elder siblings looked after him well. His sister Deborah took him into her family home, and his brother Stephen planned out his education, so that by the age of thirteen he was apprenticed to a surgeon in nearby Chipping Sodbury. Edward was a happy, self-absorbed child, obsessed with fossil hunting and natural history. By the time he was nine he had a large collection of dormouse nests and would always carry a large pocketbook to record his observations. He could never walk past a butcher’s shop without peering at the various organs on display in case they revealed something anatomically interesting. He maintained his interest in such things throughout his life, long after he became famous. As an old man, he was delighted to be the first to find and identify the fossilized bones of an aquatic dinosaur (the plesiosaur) near his home. To him, fossils were no dusty old bits of rock; they were “monuments to departed worlds.”

Edward Jenner would have appreciated Epicurus’s belief that happiness comes from living an unobtrusive life. “As for fame, what is it?” he wrote to a friend. “A gilded butt for ever pierced with the arrows of malignancy.” But, try as he might, anonymity was not to be his destiny. Aged twenty-one, he went to London to study anatomy, physiology, and midwifery under the eminent surgeon John Hunter (1728–93). Hunter was the most distinguished anatomist of his day, and it was he who encouraged Jenner to experiment rather than speculate about his scientific ideas. His motto was: “Don’t think, try!” On his two acres of land at Earl’s Court, Hunter kept ostriches, leopards, buffalo, jackals, and snakes, all for his students to carve up and investigate. If need be, he supplemented his supply by bringing in the carcasses of exotic beasts from the Royal Zoo at the Tower of London.

In 1771, when Joseph Banks returned from James Cook’s first voyage, Hunter recommended Jenner to catalog his botanical collection. Banks agreed, and was so impressed with Jenner’s work that he invited him to join Cook’s second voyage in 1772. After some hard thought, Jenner decided against it and went back home to set up his own general practice in Gloucestershire. He had also turned down John Hunter’s offer of a partnership, but the two men kept in close touch, with Hunter directing Jenner’s research into natural history by letter. After Jenner suffered a romantic setback, Hunter wrote to him, saying:

Let her go, never mind her. I will employ you with hedge-hogs, for I do not know how far I may trust mine. I want you to get a hedge-hog in the beginning of winter and weigh him; put him in your garden, and let him have some leaves, hay or straw, to cover himself, which he will do; then weigh him in the Spring and see what he has lost.

Jenner was fascinated by hibernation and skeptical of contemporary theories that birds (like bats) hibernated in winter. He dissected them and found seeds that came from other countries. He also noted that returning swallows were not, in fact, “dirty”—going against the prevailing wisdom that they spent the winter asleep in the mud at the bottom of ponds.

His work on bird migration wasn’t published until the very end of his life, but it was an earlier piece of birdlife research that first made his name. In 1787, his “Observations on the Cuckoo” revealed that cuckoo chicks have hollows in their backs, allowing them to scoop up the other baby birds in the nest and tip them over the side. This unique feature is present for only the first twelve days of the cuckoo’s life. Until Jenner’s publication, it had been assumed that it was the foster birds that got rid of their own chicks. His theory wasn’t universally accepted until photography confirmed he was right in the twentieth century, but it was good enough to get him elected to the Royal Society in 1789.

Close observation was Jenner’s forte and it led to another breakthrough: he was one of the first doctors to make a connection between arteriosclerosis of the coronary arteries and angina. In 1786, he noted that in one of his patients who had suffered from angina, the coronary arteries were “blocked” with a “white fleshy cartilaginous matter” that made a grating sound when he cut through them. “The heart, I believe,” he wrote, “in every subject that has died of the angina pectoris, has been found extremely loaded with fat.”

Jenner thoroughly enjoyed life in Gloucestershire. He was a popular country-house guest, highly regarded as a witty raconteur, poet, and violinist. He was also a natty dresser. According to his friend Edward Gardner, he was usually to be seen in “a blue coat, and yellow buttons, buckskin, well polished jockey boots with silver spurs, and he carried a smart whip with a silver handle.” Like Ben Franklin and Epicurus, he loved like-minded company, and founded two clubs: the Convivio-Medical Society and the Medico-Convivial Society. They met in separate inns and had, as their names imply, similar interests but opposite priorities. Jenner was also a keen balloonist, a hobby that terrified the local farmers but was to lead him to his future wife, Catherine: His unmanned, varnished-silk balloon landed in the grounds of her father’s estate.

Edward and Catherine were married in 1788 and had four children. The eldest, Edward, died of tuberculosis, aged twenty-one. Jenner was devastated but, ever the scientist, used the blood from his son’s frequent bleedings to enrich his manure to see if it had any effect on the growth of plants.

He was forty-seven when he made the discovery that would make him famous. By the late eighteenth century, 60 percent of the population of Europe was infected with smallpox. A third of those who contracted the disease died and survivors were left horribly disfigured. Elsewhere in the world, the toll was even worse: An estimated 95 percent of the indigenous peoples in the Americas perished from the disease after the conquistadores brought it with them in the fifteenth century. When Jenner was a child, the only hope of staving it off was a process called variolation (variola was the scientific name for smallpox, from the Latin varius, “spotty”) where dried smallpox scabs were rubbed into a cut on the hand in the hope that the body would develop resistance to the full-blown disease. It was reasonably effective, but the side effects were unpleasant and the risk of contracting smallpox remained unacceptably high.

Jenner had suffered the discomfort of variolation as a child—it also involved being starved and purged—and though he introduced it to his village practice as a standard procedure, he began experimenting to see if a safer alternative could be found. Among his patients, he noticed that milkmaids rarely caught smallpox but regularly needed treating for cowpox, a related but much less virulent infection contracted from milking cows. He wondered if country lore that cowpox protected you from smallpox might have some basis in truth.

On May 14, 1796, he took some discharge from cowpox pustules on the hand of a milkmaid called Sarah Nelmes and inserted it into an incision in the arm of eight-year-old James Phipps, the son of his gardener. Other than a slight fever, Phipps was fine. Six weeks later, Jenner inoculated him with pus from a smallpox sufferer. Again, no reaction. This wasn’t the first time it had been tried—a Dorset farmer called Benjamin Jesty had deliberately infected his wife and children with cowpox during a local smallpox epidemic twenty years earlier—but it was the first time it had been done scientifically. Two years later, having performed the procedure, which he named vaccine inoculation, or vaccination for short (from the Latin vacca, “cow”), on more than twenty patients, Jenner published the paper that would change everything: Inquiry into the Causes and Effects of the Variolae Vaccinae … known by the name of the Cow-pox (1798).

The conclusion that Jenner reached was that the cowpox vaccine was safer than variolation and provided indefinite protection against smallpox. It could also be inoculated person to person. News of the Inquiry spread all over the world, and within two years it had been translated into Latin, German, French, Italian, Dutch, and Spanish. Jenner’s life changed overnight. “I have decided,” he declared, “no matter what trials and tribulations lie before me, to dedicate the whole of my life to ridding the world of smallpox.” This modest country doctor became “the Vaccine Clerk to the World,” sending samples of his vaccine to everyone who needed it. In his own garden at Berkeley, he built a small hut, which he called the Temple of Vaccinia, where he vaccinated the poor for free. He was feted by London society; was presented to George III and Queen Charlotte; met the tsar of Russia and the king of Prussia; received the freedom of the cities of London, Dublin, Edinburgh, and Glasgow; and was awarded honorary degrees from Oxford and Cambridge.

Messages of admiration flooded in from all over the world. Thomas Jefferson wrote offering “to render you my portion of the tribute of gratitude due to you from the whole human family. Medicine has never before produced any single improvement of such utility.” Native Americans sent him a wampum belt and taught their children his name, which they commended to the Great Spirit. The British MP William Wilberforce commented that there was “no man who is so much inquired after, by Foreigners when they arrive in this country.” Jenner even corresponded with Napoleon, securing the release of two English prisoners, one of them a relative. Napoleon had already issued instructions for the mass vaccination of the French people. “Ah Jenner,” he exclaimed, “I can refuse him nothing.”

Not everyone was convinced: The variolators saw the vaccine as a serious threat to business, and other doctors questioned whether Jenner’s sampling and recording methods were rigorous enough. Some patients were wary, too—scared that they might sprout horns or udders if excretions derived from cows were injected into them. But both the army and navy promptly adopted vaccination as standard procedure and many of Britain’s most eminent physicians came out in Jenner’s support. Nevertheless, the medical authorities dragged their feet: It took until 1840 for the government to set up a national program of free vaccination.

By then, Jenner had been dead for seventeen years. In 1815 his wife, like his eldest son, fell victim to tuberculosis, and Jenner himself, increasingly infirm and tired of the public attention, returned to his haven at Berkeley. He remained there until his own death eight years later. A year before he died, he was appointed Physician Extraordinary to George IV.

In his last years, Jenner occasionally treated patients, but spent of most his time out among nature, his original inspiration, finishing his investigations into the migration of birds and importing and propagating exotic fruits. He also made arrangements to help James Phipps, the cowpox guinea pig, who had also fallen ill with tuberculosis. Poor Phipps had been variolated at least twenty times after Jenner’s original experiment by other doctors keen to test the results for themselves. As a mark of gratitude, Jenner designed and built Phipps a small cottage and personally supervised the laying out of the garden and vegetable patch that went with it. Of the other players in the cowpox drama, nothing more was heard of the milkmaid Sarah Nelmes, but the hide of her cow Blossom still hangs in St. George’s Hospital, Tooting. The cow’s horns—rather like bits of the True Cross—have multiplied since her death: At least six “authentic” pairs have been recorded.

It’s hard to overstate Jenner’s legacy. He founded the discipline we now call immunology. The modern equivalent of his discovery would be if a cure for cancer were announced tomorrow. Smallpox, the speckled devil, “the most dreadful scourge of the human species” for millennia, was declared finally eradicated by the World Health Organization in 1980, just as Jenner had predicted it would be back in 1801.

The joy I felt as the prospect before me of being the instrument destined to take away from the world one of its greatest calamities was so excessive that I found myself in a kind of reverie.

What is truly admirable is Jenner’s attitude. He knew he was right; he never gave up; he didn’t try to profit from his discovery. He just took quiet pleasure in being the right man in the right place at the right time.

There was nothing quiet about Mary Seacole (1805–81), although she, too, was an exceptional healer. The Jamaican-born heroine of the Crimean War, forgotten for almost a hundred years, has recently been rediscovered and restored to her rightful place as one of great characters of the nineteenth century.

The daughter of a Scottish soldier and a Jamaican nurse, Mary Grant grew up in a boardinghouse for sick and disabled members of the armed forces, run by her mother in Kingston, Jamaica. As a teenager, she made her way to England on her own, paying her way with a suitcase full of exotic West Indian pickles. When she returned home to take over the running of the boardinghouse, she was able to combine her knowledge of traditional Caribbean healing with the latest Western medical ideas she had picked up in London. In 1836 she married Edwin Horatio Hamilton Seacole, an English merchant resident in the house, who was rumored to be the illegitimate son of Horatio Nelson and Lady Hamilton. But her happiness was tragically short-lived. In 1843 a fire wrecked the boardinghouse, and the following year Mary’s husband and mother both died. Grief-stricken and penniless, Mary left Jamaica for a second time to join her brother in Panama, where they jointly ran a hotel. It was there that she first got to practice her medical skills in earnest, nursing the victims of outbreaks of cholera and yellow fever—with remarkable results. Her method was based on careful observation of the symptoms of each individual patient: “Few constitutions permitted the use of exactly similar remedies, and … the course of treatment which saved one man, would, if persisted in, have very likely killed his brother.” Although some of her medications, like sugar of lead, probably did more harm than good, her attentiveness and general empathy with the suffering of those in her care offered a holistic approach to healing that was ahead of its time.

Encouraged by her success, she applied to the British War Office to serve as a nurse in the Crimea. Never one to under-dramatize her life, Mary wrote that she wanted to experience “the pomp, pride and circumstance of glorious war.” Needless to say, a loud and rumbustious fifty-year-old woman of mixed race and brightly colored attire was not what either Florence Nightingale or the War Office was looking for. Though laden with letters of recommendation, each of her several applications was rejected.

But Mary was undeterred. She had grown up surrounded by British soldiers and was convinced that her “sons,” as she called them, would need her special form of bedside care. So she borrowed some money, bought a one-way ticket, and printed some business cards:




(Late of Kingston, Jamaica),

Respectfully announces to her former kind friends, and to the Officers of the Army and Navy generally,

That she has taken her passage in the screw-steamer Hollander, to start from London on the 25th of January, intending on her arrival at Balaclava to establish a mess table and comfortable quarters for sick and convalescent officers.

It was an astounding declaration, but she was as good as her word. In Balaclava, she bumped into an old business colleague of her husband’s, Thomas Day, and they set up a partnership. Using local laborers and any materials they could salvage—packing cases, driftwood, scrap metal—they built a small hotel. It opened in March 1855, on the main supply route to Sevastopol, two miles from the front line.

The British Hotel became a Crimean institution. The restaurant alone was legendary—Mary’s rice puddings and sponge cakes reminded the troops of home—but the hotel also served as a bar, a hospital, and a general store that stocked anything from “a needle to an anchor.” From there each day Mary would ride to the trenches surrounding Sevastopol, sometimes under fire, with two mules—one carrying medicine, the other food and wine—to nurse and feed the wounded. Known to all as “Mother Seacole,” she was a warm, reassuring presence amid the slaughter, dressed in startling combinations of yellow, blue, and red. She was on hand to care for the British after the ill-fated assault on the Redan outside Sevastopol in June 1855, in which a quarter of the men were killed or wounded. Two months later, after the battle at the Tchernaya River, she tended wounded Russians as well as French and Italians but was ready the next day to throw “a capital lunch on the ground” at a British regimental cricket match. In September, when Sevastopol finally fell to the allies, after a horrific yearlong siege in which a hundred thousand Russians died, Mary Seacole was the first woman to enter the burning city.

In 1856, the war over, Mary set off for England, penniless for the third time, ill, alone, and pursued by creditors. This would have been an unthinkable disaster for most women of her age, but she was unbowed: “I do not think I have ever known what it is to despair, or even to despond,” she wrote later. She took to wearing medals to remind people of her outstanding service to the military cause (although there is no record she was ever awarded any) and within a few months had mobilized her friends in the upper echelons of the army and the popular press to set up the Seacole Fund to save her from bankruptcy. It did that and more. In July 1857 the fund staged a four-day festival featuring more than a thousand performers, including eleven military bands. It was a kind of SeacoleAid, attended by a crowd of forty thousand people.

A month earlier, Mary had published her autobiography, the Wonderful Adventures of Mrs. Seacole in Many Lands. It was bound in bright yellow boards, with scarlet lettering and a portrait of Mary on the front in military garb, wearing a Creole kerchief and an extravagantly feathered hat. If that didn’t pull in the Victorian reader, the opening paragraph was a real lapel grasper:

All my life long I have followed the impulse which led me to be up and doing, and so far from resting idle anywhere, I have never wanted inclination to rove, nor will powerful enough to find a way to carry out my wishes.

With its vivid and moving account of the war, it became an immediate bestseller and cemented Mary’s celebrity status.

The last twenty-five years of Mary’s life were (by her somewhat frenzied standards) restrained and comfortable, and she died at her house in Paddington in 1881, aged seventy-six. Both the Times and the Manchester Guardian ran glowing obituaries. Her subsequent disappearance from the public record is usually blamed on the preeminence of Florence Nightingale, who, as we all know, invented modern nursing at her Crimean hospital in Scutari. This is unfair to both women. Mary Seacole was a doer, a force of nature. She restored people’s souls as well as their bodies. It’s appropriate that she has become a role model for the medical profession only now, after a century of more mechanistic medicine. But she invented no system, left no legacy. And she ran hotels, not hospitals—as Florence Nightingale was keen to point out. In 1870 the Lady with the Lamp wrote a rather vinegary letter to her brother-in-law complaining about Mary’s “bad character” and summing up her contribution to the war effort. “She was very kind to the men &, what is more, to the Officers—& did some good—& made many drunk.”

Florence Nightingale’s disdain raises another issue: Mary’s color. Was she the victim of prejudice? She certainly thought so. Reflecting on her rejection by the War Office, she wrote: “Did they shrink from accepting my aid because it flowed from a somewhat duskier skin than theirs?” In the 1970s, this became a rallying cry for disgruntled black nurses in the British National Health Service, marking the beginning of a process of rehabilitation for Mary Seacole that ended in her being voted the greatest Black Briton of all time and becoming a settled fixture in the national curriculum.

Ironically, Mary didn’t consider herself “black” at all. She came from Jamaica, where the subtleties of skin coloring mattered intensely. She called herself a Creole “with good Scotch blood coursing in my veins.” Her father was white and her mother probably mixed race. In Jamaica this meant she was a Free Colored, less constrained and more socially acceptable than the black former slaves, but still definitely not white. As she wrote in her memoir: “I am only a little brown—a few shades duskier than the brunettes whom you all admire so much.” And she was fiercely proud of being British. One of the things that make her autobiography so compelling is the firsthand account of nineteenth-century racism and her sense of disappointment that skin color should matter at all. There is one powerful exchange from her time in Panama where a “sallow-looking” American toasts her for all she has done to stem disease in the colony, adding: “If we could bleach her by any means we would—and thus make her as acceptable in any company as she deserves to be.” Mary’s response is magnificent:

Providence evidently made me to be useful, and I can’t help it. But, I must say, that I don’t altogether appreciate your friend’s kind wishes with respect to my complexion. If it had been as dark as any nigger’s, I should have been just as happy and as useful, and as much respected by those whose respect I value; and as to his offer of blessing me, I should, even if it were practicable, decline it without any thanks. As to the society which the process might gain me admission into, all I can say is, that, judging from the specimens I have met with here and elsewhere, I don’t think that I shall lose much by being excluded from it. So, gentlemen, I drink to you and the general reformation of American manners.

The Wonderful Adventures deserves its newfound status as a modern classic. It was written for money and can be monstrously self-promoting in places, but at its best—in the tender accounts of the young men who died in her arms, or by abruptly breaking off from describing battlefield carnage to give a recipe for a refreshing punch—it is as lively and original as the lady herself.

Despite all her troubles, Mary lived and died a happy woman. She may never have heard of Epicurus but she instinctively embodied his central proposition that true pleasure comes from conquering pain and fear. And in the other sense of the word, what could be more Epicurean than a bar and restaurant on a battlefield? She left no grand edifice, but she left an unforgettable voice.

Everything we know about Mary Frith, better known as Moll Cutpurse (about 1584–1659), suggests that her voice was equally unforgettable. For one thing, she had to make herself heard above the roar of the bear pit. Standing among the office blocks and art galleries of London’s Bankside today, it’s hard to imagine that four hundred years ago, in a small street still called Bear Gardens, ferocious battles were fought in a circular arena that held more than three thousand people. Here could be seen the most formidable fighting bears of the era—ursine celebrities like Ned Whiting, Sackerson, or Blind Harry Hunks—taking on a succession of dogs, swatting them from wherever their jaws had fastened hold, battling it out until either they or the dogs collapsed from exhaustion. As well as being a noisy, gruesome spectacle, bear baiting was big business. A lot of money could be made betting on the outcome.

It was a brutal, often dangerous pastime. The animals were tethered to a stake in the center of the arena, held by a 15-foot chain or rope. The breeders stood in a circle, just out of range, holding their dogs by the ears. Once they were let loose, the contest would rage for as long as an hour. It wasn’t unusual for wounded animals to break free and chase their owners around the pit. Injuries were common; health and safety rules rudimentary. This was a man’s sport: the bear pit was no place for a woman.

But Mary Frith wasn’t going to let that put her off. She dressed, drank, smoked, and swore like a man; and the bear pit was her passion. She bred mastiffs—the muscular, squat-faced, short-necked, strong-jawed ancestors of today’s bulldogs. In her own account of her life, published in 1662, three years after her death, we learn that her dogs were pampered like the children she never had (or wanted), each of them sleeping in their own bed, complete with sheets and blankets, and fed on a special food she boiled up herself.

Mary had grown up just over the river, the daughter of a cobbler in Aldersgate Street, but Southwark was her spiritual home. The south bank of the Thames in the early seventeenth century was London’s pleasure center, though very much not what Epicurus had in mind. Two pence got you into the bear garden; six pence, an evening at the theatre or an hour with a whore. Beer was a penny a pint; tobacco, three pence a pipe load; a decent tavern meal about the same. Given that the average wage was about seven shillings a week, it’s not surprising that theft and gambling were rife. The entertainments brought in huge numbers of gamblers: An estimated 10 percent of the entire population of London visited the theatre or the bear garden every day. In the narrow maze of streets, gangs of professional criminals worked their routines assiduously.

Mary Frith started out as a pickpocket. We first hear of her as a teenager in 1600, when she and two female accomplices were accused of stealing “2s and 11d in cash, from an unknown man at Clerkenwell.” Other arrests followed, and despite her protestations in her autobiography that she “never Actually or Instrumentally cut any Mans Purse,” she certainly worked as a part of a gang who did. But Mary had grander ambitions than a life of petty crime. By 1608 she was performing in the streets and taverns of Southwark. Dressed as a man, in a doublet and leather jerkin, a sword hanging by her side and a pipe clamped between her teeth, she would strum her lute, sing rude songs, dance jigs, and tell stories. Perhaps the cross-dressing began as part of her pickpocket routine—it would certainly have made it easier it to blend into a crowd—but it soon became her calling card.

A woman dressing as a man was far more shocking then than now. It was done in the theatre, of course—all the actors were men and boys in any case—but to do it openly on the streets was more than just an affront to the natural order of things. It was breaking the law. Moll Cutpurse, Mary’s alter ego, became an overnight sensation. She was more like a contemporary conceptual artist than the stage performers she hung around with—not only did she dress and perform as a man, she lived like one, too. From the tavern to the bear pit, her art was her life. By 1610, she had inspired one of the first female celebrity biographies, The Madde Prancks of Merry Moll of the Bankside with Her Walks in Man’s Apparel and to What Purpose, by the playwright John Day. In 1611 two of the most successful writers of the age, Thomas Dekker and Thomas Middleton, asked her to close a performance of the play they had written about her, The Roaring Girl. This was the big time—an audience of two thousand people watching Moll Cutpurse playing herself.

This stunt proved too much for the authorities. Mary was arrested for immoral behavior and thrown into the correction house at Bridewell, where she was subjected to the punishment usually reserved for prostitutes. She was soundly whipped and then forced to beat the stalks of hemp plants to make fibers for rope. But if this was intended to make her see the error of her ways, it failed abysmally. After three months, she reemerged and took up where she had left off. On Christmas Eve, 1611, she was arrested again for exactly the same offense, “to the disgrace of all womanhood.”

This time she was hauled up in front of the bishop of London, charged with prostitution as well as cross-dressing. The bishop pressed her to confess that she was “sexually incontinent,” but Mary would have none of it. She cheerfully admitted to being a foul-mouthed, drunken thief and a gambler and a bear baiter, but she strongly objected to the accusation that she had sold her body. Though she looked like a man, she told the assembled clerics, a visit to her lodgings would show she was every bit a woman. This saucy response outraged the judge. She was sentenced to public penance (dressed in a very unmanly white shift) at the cross outside old St. Paul’s. Mary turned it into a command performance, drinking herself insensible on six pints of sherry first and then weeping so piteously that the authorities released her to preserve the peace.

Mary had a very modern instinct for making money from fame. By the time she was thirty, she was a major player in the London underworld. Her days as a thief and her hours spent in the bear gardens and taverns had built up an unrivaled network of contacts on both sides of the law. As far as her manor was concerned, she always knew who was doing what, and where. This made her the perfect broker for stolen goods. If a purse or a watch went missing, a visit to Moll Cutpurse would usually see it restored on the same day, provided a decent cash reward was produced. It was a protection racket tolerated by the authorities because it kept the mean streets of Southwark under control, and welcomed by the theatres and sporting rings because it allowed them to turn a profit unmolested.

In 1614 Mary married Lewknor Markham, scion of a well-off, upper-class family from Nottinghamshire. Mary’s new father-in-law, Gervase Markham (1568–1637), was an astonishingly industrious author, churning out poems and treatises on everything from forestry, agriculture, and military training to veterinary medicine, archery, and wildfowling. The booksellers were swamped with his works. In 1617 he had five different books on horses all in print at the same time. This exasperated the Stationers’ Company, which forced him to sign an unprecedented agreement in which he promised “never to write any more book or books to be printed of the deseases or Cures of any Cattle, as Horse, Oxe, Cowe, Sheepe, Swine, Goates etc.” His best-known work is The English Hus-wife (1615), a kind of early Mrs. Beeton, full of recipes and handy hints on running a successful household. Quite what drove his son to marry a cross-dressing, bear-baiting gangster is a mystery.

In any event, it seems to have been a marriage of convenience rather than passion, as there is no evidence of their ever having lived together. From Mary’s point of view, having a husband brought respectability, which was good for business. She invariably referred to herself as Mrs. Mary Markham from then on, although she failed to mention her husband at all in her autobiography. In fact, other than the marriage, there is no mention of Lewknor Markham in any historical records. The couple married at St. Mary Overbury, now Southwark Cathedral, at that time the actors’ church, so it’s possible he was involved with the theatre. Why did he marry Mary? Perhaps he was gay? That wouldn’t have been unusual in the Southwark of the day. Or given that the subtitle to The English Hus-wife was “Containing the Inward and Outward Virtues Which Ought to Be in a Complete Woman,” it might have just been two fingers up to his annoyingly successful father. But the most likely reason is money, Lewknor taking a cut from Mary’s business in return for use of the Markham name. That would have been worth hard cash to her.

Mary’s sex life is another mystery. There’s no record of her having had sexual relationships with anyone, male or female. However scary Moll Cutpurse may have been in public, the private Mary Frith sounds rather nice, and her house in Fleet Street, full of dogs and parrots, surprisingly feminine. It was always immaculate—kept spotless by no fewer than three maids—and the walls were covered with looking glasses, “so that I could see my sweet self all over in any part of my rooms.” Self-esteem was clearly not the problem. On rare occasions she did admit to finding a man attractive—one such was Ralph Briscoe, the clerk at Newgate Prison, who was “right for her tooth” and whose life she saved by pulling him out of the ring when a bull had him by the breeches. But sex just seems to have been too much bother, except as a source for humor. Coming across a worse-for-wear neighbor late one night, she called out to him cheekily: “Mr. Drake, when shall you and I make Ducklings?”

To which he responded “that I looked as if some Toad had ridden me and poisoned me into that shape,” that he was altogether for “a dainty Duck, that I was not like that Feather, and that my Eggs were addle. I contented my self with the repulse and walked quietly homeward.”

Good humor, self-deprecation, vulnerability are all there. Perhaps she was happier alone with her dogs and parrots, who loved her unconditionally.

The lusts of others were a different matter. Hovering between the criminal underworld and polite society, Mary was perfectly placed to offer more intimate services than the sale of stolen property. And she had spotted a gap in the market: wealthy women looking for male companions. With the single-mindedness she brought to all her business ventures, she “chose the sprucest Fellows the Town afforded” and turned her house into an escort agency. One of her most audacious coups was to get the male lovers of a woman who had been (with Mary’s help) serially unfaithful to her husband to contribute to the maintenance of her children after she’d died of the clap.

Busy as she was with fencing and pimping, Mary still found time to play Moll for the occasional public performance. The vintner and showman William Banks bet her £20 that she wouldn’t ride from Charing Cross to Shoreditch dressed as a man. Of course, she did so in style, flaunting a banner, blowing a trumpet, and causing a riot in the process. Part of the excitement was due to the fact that the horse she was riding was Banks’s Morocco, the most famous performing animal in London. Shod in silver, it could dance, play dice, count money, and generally astonish an audience with its intelligence and dexterity. Its most famous trick was climbing the hundreds of narrow steps to the top of the old St. Paul’s and dancing on the roof, watched by thousands below. In the annals of popular entertainment, Moll Cutpurse riding Banks’s horse would have been the Jacobean equivalent of the Beatles reforming and playing on the same stage as the Rolling Stones.

Even at four centuries’ distance, it is this irrepressible side to Mary’s character that seems as fresh as ever. If the idea of bawdy has fallen victim to endless over-the-top costume dramas, full of ale-swigging wenches in low-cut dresses, it’s worth remembering the word originally meant “joyous.” The joy that Mary brought to others with her unconventional life was borne out by the people who knew her. “She has the spirit of four great parishes,” wrote Middleton and Dekker, “and a voice that will drown all the city.” She was a show-off—even sometimes a bully—but the dens and alleyways of south London were a brighter place for her presence. One can imagine her getting on well with Mary Seacole. Both rose from poverty and lived their lives as independent women, on their own terms, in a man’s world.

After the Civil War, the Puritans banned bear baiting. Though Mary outlived Cromwell, she didn’t live quite long enough to see the monarchy restored and her beloved bear garden reopened, but in any case, the Southwark of old was never quite the same again. Mary Markham died wealthy enough to be buried inside St. Bridget’s Church in Fleet Street. Her final request was to be laid face down in her coffin because “as I have in my Life been preposterous, so I may be in my Death”—but whether it was carried out, we’ll never know.

One person who would have appreciated Mary’s last wish was the great twentieth-century physicist Richard Feynman (1918–88). Tall, handsome, and funny, he was also an eccentric prankster with a huge appetite for the preposterous. His own last words were in the same spirit: “I’d hate to die twice. It’s so boring.” For Feynman, to be bored in life, work, or death was the ultimate sin.

He was born into a tight-knit Jewish family in New York and didn’t talk until he was well past three years old. Not long afterward, his father, somewhat optimistically, bought him the entire Encyclopedia Britannica. But the young Feynman devoured it: It was his constant companion throughout his childhood, and by his early teens he had read it cover to cover. His father, Melville, a Belarusian car-polish salesman, stretched him in other ways, too. He taught him to predict mathematical patterns using building blocks and took him on long walks where he showed him how to pay close attention to nature. It was his father, Feynman always said, who taught him the difference between “knowing the name of something and knowing something.” Years later he would write:

You can know the name of a bird in all the languages of the world, but when you’re finished, you’ll know absolutely nothing whatever about the bird. So let’s look at the bird and see what it’s doing—that’s what counts.

Melville also had a wonderful knack of turning abstract scientific ideas into stories, something his son would inherit and make his trademark:

For example, when I was playing with my electric trains, he told me that there is a great wheel being turned by water which is connected by filaments of copper, which spread out and spread out and spread out in all directions; and then there are little wheels, and all those little wheels turn when the big wheel turns. The relation between them is only that there is copper and iron, nothing else—no moving parts. You turn one wheel here, and all the little wheels all over the place turn, and your train is one of them. It was a wonderful world my father told me about.

As a result, science and fun were indistinguishable for the young Feynman. He accumulated tubes, springs, batteries, anything mechanical he could get his hands on, and performed experiments. He paid his younger sister Joan (who also became a physicist) four cents a week to act as his lab assistant. Part of her role was to agree to be electrocuted (mildly) in front of Dick’s friends. He also created a rudimentary burglar alarm for the house and an electric motor that would rock his sister’s cot. He was known in the neighborhood as “the boy who could fix radios by thinking.”

He hated school, of course—except for the Math Team, where he reigned supreme. In the school yearbook, he was given the soubriquet Mad Genius, which he did his best to live up to. Studying for his bachelor’s degree at the Massachusetts Institute of Technology, his math and physics results were off the scale, and later, in the entrance exam for Princeton, he achieved a perfect score in both subjects—a feat never achieved before or since. Feynman’s happiest times at the university were spent playing in his room, trying to figure out how ants communicated or the physics required to explain how jelly set. Nevertheless, his doctoral thesis caused a sensation. In it, he created an entirely fresh approach to quantum mechanics—unlike anything anyone had done before—and applied it with spectacular success to describe the interactions of electrons and photons. Rather as Oliver Heaviside had done with Maxwell’s equations for electromagnetism, the twenty-three-year-old Feynman had come up with a simpler, more elegant solution than anyone had thought possible. He later claimed that he had a synesthetic gift: He could see the underlying patterns in a sequence of equations marked out in different colors.

This unconventional brilliance earned him a junior role in the Manhattan Project, helping to develop the atomic bomb at Los Alamos in New Mexico. Glamorous though this sounded, he soon got bored: “There wasn’t anything to do there,” he complained. To while away the time, he taught himself to pick the combination locks on the security complex’s top secret filing cabinets, or disappeared into the desert to chant and drum in Native American style, gaining himself the nickname Injun Joe. Despite his initial euphoria at the success of the tests (typically, he was the only one to see the bomb explode without protective glasses, reasoning—correctly—that a car windscreen was sufficient to screen out the harmful alpha radiation), he later regretted his involvement, likening it to tickling the tail of a sleeping dragon.

In 1948 he won the Nobel Prize for Physics. He was only thirty. As with his graduate thesis, the prize was awarded for improving and clarifying the work of others. Quantum electrodynamics (QED) was the discipline that explained the behavior of light, magnetism, and electricity, but it was irritatingly unreliable. With two other physicists, Feynman fixed the flaws in the theory, but his most important contribution was to describe the motions of subatomic particles using a sequence of small, elegant diagrams. He always downplayed the work he did at this period as so much “mathematical hocus-pocus,” but he liked his Feynman diagrams enough to paint them all over his van. They are still the best way of describing the quantum world.

The major portion of Feynman’s professional life was spent at the California Institute of Technology (Caltech). It is sometimes said of him that although he was unquestionably one of the great physicists of any century, he didn’t make a major theoretical breakthrough or give his name to an important new discovery. That may be less to do with him than the nature of physics in the period—few of his contemporaries could claim to have done so either. It also obscures what is Feynman’s greatest achievement: He was the best and most charismatic teacher of his generation. He loved teaching and believed that if a theory couldn’t be explained to a nonscientist, there was something wrong with the theory. In the introduction to his bestselling collection of lectures, he tells his audience:

What I am going to tell you about is what we teach our physics students in the third or fourth year of graduate school … It is my task to convince you not to turn away because you don’t understand it. You see my physics students don’t understand it. That is because I don’t understand it. Nobody does.

But this, as he explains, is neither demoralizing nor defeatist:

We can imagine that this complicated array of moving things which constitutes “the world” is something like a great chess game being played by the gods, and we are observers of the game. We do not know what the rules of the game are; all we are allowed to do is to watch the playing. Of course, if we watch long enough, we may eventually catch on to a few of the rules. The rules of the game are what we mean by fundamental physics.

Feynman always described his physics as “fiddling about” or “a game.” For him, it was play rather than work: just a matter of looking closely, and wondering:

When someone says, “Science teaches such and such,” he is using the word incorrectly. Science doesn’t teach anything; experience teaches it. If they say to you, “Science has shown such and such,” you might ask, “How does science show it? How did the scientists find out? How? What? Where?”

He spent most of the second half of his life trying to supply intelligible answers to these questions. Perhaps the perfect Feynman moment came in the inquiry into the Challenger spaceshuttle disaster in 1986. The commission had become mired in evasions and technical obscurantism and was finding it impossible to pinpoint the cause of the accident. One suspect was the rubber O-rings used as seals between the sections of the solid fuel rockets. The failure of these immense but fragile rings—only a quarter of an inch in diameter but thirty-seven feet in circumference—would certainly have caused the disaster, but nobody could (or would) say for certain whether they had, or why. Feynman was convinced the O-rings were to blame. Live on camera, in front of the commission and all the witnesses, he cut through the whole tangle of evidence by taking a small section of O-ring and dipping it into a glass of iced water. It was immediately obvious to everyone that the rubber instantly lost its elasticity at cold temperatures, which would have caused the seals to fail and the rocket to break up. On that fateful morning, the temperature had been 24° F lower than the engineers recommended. Case closed. It was science at its simplest and most powerful: Epicurus would have been proud.

The rest of Feynman’s life can sometimes look like a parody of the groovy 1960s professor. He taught himself to play bongos in the Brazilian manner, held exhibitions of his own paintings, experimented with drugs, learned how to decipher Mayan hieroglyphs, and studied comparative religions. He had a “second office” in a topless bar in Pasadena, where he would scribble equations and new Feynman diagrams on the back of his beer mat. But these were more than the affectations of a geek:

The fact that I beat a drum has nothing to do with the fact that I do theoretical physics. Theoretical physics is a human endeavor, one of the higher developments of human beings—and this perpetual desire to prove that people who do it are human by showing that they do other things that a few other humans do (like playing bongo drums) is insulting to me.

He didn’t play the bongos because he was a physicist; he played the bongos because he was Richard Feynman, a man with a lifelong aversion to boredom. As he once wrote: “You cannot develop a personality with physics alone, the rest of life must be worked in.” In his final years, dying of cancer, he became fascinated by the central Asian republic of Tuva, researching its history and culture—particularly the throat singing, which he loved—and planning a visit. The story of his cat-and-mouse, decade-long game with Russian bureaucracy became his last book, Tuva or Bust! It’s as funny, quirky, and life affirming as you’d expect. His visa finally arrived the day after he died.

Richard Feynman’s absorption in his subject, and his defiant determination to have fun right to the end, sums up the attitude that animates each of these six lives. Each learned to be happy in his or her own skin and to do so by being positive. Of those who went to school at all, none of them was a particularly attentive pupil; they taught themselves by observing the world and people around them. The philosopher Ludwig Wittgenstein once remarked that although he wasn’t sure why we were here, he was “pretty sure that it is not in order to enjoy ourselves.” Epicurus would have had words with him about that. Enjoyment for each of the six came from doing what they loved to do. And that spirit is infectious. Who wouldn’t want to sit down to “a capital lunch” with Mary Seacole, go for a country walk with Edward Jenner, eavesdrop on Ben Franklin at a party, or spend an evening in a bar where Moll Cutpurse was singing, accompanied by Richard Feynman on bongos? This is the real meaning of genius: to expand our sense of what’s human, to cheer us up. Nietzsche—not himself, perhaps, at the top of anyone’s cheerful list, but a great admirer of Epicurus—certainly thought so: “There is one thing one has to have: either a soul that is cheerful by nature, or a soul made cheerful by work, love, art, and knowledge.”

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