In bestselling books, on websites, and with a national lobbying effort, atheists and other nontheists are challenging the growing religious influence in government and public life. Some are attacking the foundations of religion itself. Two particularly provocative books, in fact, hit the top of Publishers Weekly's religion bestseller list in December. No. 1, "The God Delusion," by evolutionary biologist Richard Dawkins, and No. 2, "Letter to a Christian Nation," by writer Sam Harris, are no-holds-barred, antireligion polemics that call for the eradication of all manifestations of faith. "I am attacking God, all gods, anything and everything supernatural, wherever and whenever...