For much of his career Flew was known as a strong advocate of atheism, arguing that one should presuppose atheism until empirical evidence of a God surfaces. He also criticized the idea of life after death,the free will defense to the problem of evil, and the meaningfulness of the concept of God.
However, in 2004 he changed his position, and stated that he now believed in the existence of an Intelligent Creator of the universe, shocking colleagues and fellow atheists.
In 2007 a book outlining his reasons for changing his position, There is a God: How the World's Most Notorious Atheist Changed His Mind was written by Flew in collaboration with Roy Abraham Varghese.
Here: The Book on Amazon