What was C.S. Lewis’s 1942 Christian apologetics book about a demon named Screwtape called?

The Screwtape Letters is C.S. Lewis’s 1942 Christian apologetics book about a demon named Screwtape. It is written as a series of letters from an experienced tempter to his junior nephew, Wormwood.

Screwtape advises Wormwood on how to undermine a human being’s faith and character. Lewis reverses the usual angle of religious instruction: instead of describing how people should resist temptation, he exposes temptation by presenting the demons’ professional viewpoint.

The book began as a series of pieces published in the Anglican newspaper The Guardian. The letters were later collected and issued as a book in 1942. Its satirical form made abstract moral and theological ideas accessible to a broad readership.

The title character is not the human being being tempted. Screwtape is the senior demon giving instructions, while Wormwood is his inexperienced trainee. That relationship is central to the book’s comic and unsettling effect.