The God Delusion (2006) is Richard Dawkins's best-selling polemic against religious belief, originally published in London by Bantam Press and in the United States by Houghton Mifflin. Written by the Oxford evolutionary biologist best known for The Selfish Gene, it became one of the central books of the movement dubbed the 'New Atheism.'
Dawkins argues that belief in a personal god is not merely mistaken but a delusion, a false belief held against strong contrary evidence. He systematically addresses the traditional arguments for God's existence, offers natural selection as an alternative to the argument from design, and contends that a creator complex enough to design the universe would itself be more improbable than what it purports to explain.
The book also examines the roots of religion and morality, arguing that ethical behavior does not depend on faith, and criticizes the influence of religion on politics, education, and social conflict. Provocative and widely debated, it drew both large readership and substantial criticism, cementing Dawkins's role as a public advocate for science and secularism.