What was the title of C.S. Lewis’s 1942 novel written as letters from a demon?

C.S. Lewis’s 1942 novel written as letters from a demon is The Screwtape Letters.

The book consists of correspondence from Screwtape, a senior demon, to his inexperienced nephew Wormwood. Screwtape offers advice on tempting a human patient, while Lewis uses the demonic perspective to expose habits such as distraction, vanity, resentment, and self-deception.

The novel was published in book form in 1942 by Geoffrey Bles. Lewis had first published the letters in the Anglican newspaper The Guardian, which is unrelated to the modern newspaper of the same name. The unusual viewpoint lets Lewis discuss moral and spiritual issues indirectly and often satirically.

Screwtape is not a traditional hero, and the book is not a handbook of occult practice. Its purpose is theological and literary: readers are meant to recognize the ordinary weaknesses that the demons exploit. Wormwood is the junior tempter receiving the letters, not the authorial narrator.