This book emerged out of the scripts that I composed for the ten-part documentary film Catholicism. The three years of planning, writing, traveling, filming, and editing that went into the production of that series constitute an unforgettable moment in my life. The many, many people who contributed to the film have helped, obviously, to shape the book that you are about to read. I am, from the bottom of my heart, grateful to Father Stephen Grunow, Mike Leonard, Matt Leonard, Nancy Ross, Diane Archibald, Peggy Pandaleon, Robert Mixa, Megan Fleischel, Patrick Thornton, Steve Mullen, Nanette Noffsinger, Brooks Crowell, Rozann Carter, Father Paul Murray, Dr. Denis McNamara, and John Cummings. I am also deeply indebted to my editor, Gary Jansen, who read the manuscript with great care and whose suggestions have resulted in a better book.