What was C.S. Lewis’s wartime book of letters from a demon to a human?

The Screwtape Letters was C.S. Lewis’s wartime book of fictional letters from a demon to a human. It was published in book form in 1942 and presents advice on temptation from the senior demon Screwtape to his inexperienced nephew, Wormwood.

Lewis uses a deliberately reversed perspective: the demons discuss how to keep a human patient spiritually confused, selfish, and distracted. The device allows him to examine pride, resentment, habit, social pressure, and moral choice without presenting the material as a conventional sermon.

The work grew from pieces first published in the Anglican newspaper The Guardian during 1941. Lewis later collected them into a book. The letters are fictional, not a claim that Lewis had received supernatural correspondence, and the demonic viewpoint is a literary framework for moral satire.

Readers sometimes confuse the book with The Great Divorce, another Lewis work involving the afterlife and spiritual choices. The Screwtape Letters is specifically epistolary: its central form is correspondence between demons.