Sam Harris is a brave man. In a country where 90 percent of adults say they believe in God, he has written a bestseller condemning religion. The End of Faith: Religion, Terror, and the Future of Reason (Norton) has won numerous awards for its meticulous and far-reaching arguments against the irrationality of religious belief. Harris has also drawn criticism from all sides, endearing himself to neither religious moderates nor fundamentalists, and even irritating atheists. His latest book, Letter to a Christian Nation (to be published this month by Knopf), is a bold attack on the heart of Christian belief. Clearly, this is someone who is not afraid to speak his mind.