Dawkins is an atheist; a freethinker, secular humanist, sceptic, scientific rationalist, and supporter of the Brights movement. He has widely been referred to in the media as "Darwin's Rottweiler", by analogy with English biologist T. H. Huxley, who was known as "Darwin's Bulldog" for his advocacy of natural selection. In his 2006 book The God Delusion, Dawkins contends that a supernatural creator almost certainly does not exist and that religious faith qualifies as a delusion-as a fixed false belief. As of November 2007, the English language version had sold more than 1.5 million copies and had been translated into 31 other languages, making it his most popular book to date.