Today there is a new movement critical of religion, the new atheism fostered by Daniel Dennett, Richard Dawkins, and Sam Harris. Harris says faith in god or gods is the most dangerous element of modern life, citing Islamic terrorism as well as Judeo-Christianity's growing weapons of mass destruction. Dawkins says the biblical Yahweh is psychotic, and religion is not only nonsense but a divisive and oppressive force. Dennett describes the God Delusion and hopes that practitioners of religion will shrink its maleficent role in civilization. The question addressed in this book, Is God Necessary?, is not new but is of perennial importance. What is new is that a great new discovery answers this question decisively in the twenty-first century as Darwin's theory of evolution did in the nineteenth century.