Why I Am Not a Christian is an essay by the British philosopher Bertrand Russell. Originally a talk given 6 March 1927 at Battersea Town Hall, under the auspices of the South London Branch of the National Secular Society, it was published that year as a pamphlet and has been republished several times in English and in translation.
Russell begins by defining what he means by the term Christian and sets out to explain why he does not "believe in God and in immortality" and why he does not "think that Christ was the best and wisest of men", the two things he identifies as "essential to anybody calling himself a Christian". He considers a number of logical arguments for the existence of God and goes into specifics about Christian theology. He argues ad absurdum against the "argument from design", and favors Darwin's theories.
Russell also expresses doubt over the historical existence of Jesus and questions the morality of religion, which is, in his view, predominantly based on fear.
The first German edition was published in 1932 by Kreis der Freunde monistischen Schrifttums, a monist association in Dresden inspired by Ernst Haeckel. In 1957 Paul Edwards preferred Russell over the then more trendy Ludwig Wittgenstein and published the essay and further texts referring to the background of The Bertrand Russell Case. Russell had been denied a professorship in New York for his political and secular views and his tolerance for gay and lesbian behaviour among students. Some countries banned the book, including South Africa. The enhanced version has been republished in various editions since the 1960s. The New York Public Library listed it among the most influential books of the 20th century.