With roughly 9 in 10 of its citizens claiming to believe in God or a Supreme Being, America is widely acknowledged to be the most religious of modern industrial nations. Yet when it comes to knowledge about religion, it ranks among the most ill-informed. While close to two thirds of all Americans regard the Bible as a source of answers to life's questions, only half can name even one of the New Testament Gospels. Similarly, in a land of growing religious diversity, only 10 percent of U.S. teenagers can name the world's five major religions. Stephen Prothero, the head of the department of religion at Boston University, calls this condition a "major civic problem." His new book, Religious Literacy, tells how we got here—and how we might do better.