Screwtape is a fictional devil in a book The Screwtape Letters (1942) and its sequel short fiction Screwtape Proposes a Toast (1959), both written by the Christian author C. S. Lewis. Screwtape is also the title of the stage adaptation of the Letters by James Forsyth (originally Dear Wormwood, 1961).
Screwtape is a Senior Tempter and the Undersecretary of his department. The Letters are his side of the correspondence with his nephew Wormwood, as mentor to the young devil who is charged with the guidance of one man. The Toast is Screwtape's after-dinner speech at the Tempters' Training College and is a satire on American and British or English public education.
Screwtape appears to understand very well the nature of human minds and weaknesses, although nothing about love. He also has a way with words and a fondness for sarcasm.