A new unauthorized biography of "America's pastor" Rick Warren uncovers a marriage with an unconventional beginning and a time of depression that later gave Warren the strength to become who he is today. Jeffery L. Sheler, religion correspondent for U.S. News and World Report, delves into the world of Warren in his latest book, Prophet of Purpose: The Life of Rick Warren. The book portrays the affable yet confident megachurch pastor who calls presidents and billionaires his friends in a much more vulnerable light. In a live Web discussion with Christianity Today editor-in-chief David Neff on Wednesday, Sheler talked about...