'The Screwtape Letters' is a novel authored by C S Lewis in a series of 31 Christian apologetic letters first published in the period from May 1941 to November 1941 in The Guardian. These letters have been classified in both fiction and non-fiction categories. The letters are addressed to his nephew Wormwood by the senior Demon bureaucrat Screwtape. He mentors Wormwood, a Junior Tempter on his responsibility for securing the damnation of a British man known only as "the Patient". These letters are a series of lessons in the importance of living out Christian faith with all the temptations and failings in life. Screwtape gives Wormwood detailed advice on various methods of undermining faith and promoting sin in the Patient with observations on human nature and Christian doctrine. The preface was added to these letters by C S Lewis in 1961.Screwtape Proposes a Toast was first published in 1959.

It is the sequel of The Screwtape Letters in which certain trends in public education are criticized.