Which C.S. Lewis work is narrated by the demon Screwtape through letters to his nephew Wormwood?

The Screwtape Letters is narrated through letters from the senior demon Screwtape to his nephew Wormwood. C.S. Lewis published the work in book form in 1942.

The fictional correspondence reverses the usual viewpoint of moral instruction: Screwtape advises Wormwood on how to tempt a human being away from God. By presenting the advice as demonic strategy, Lewis examines pride, distraction, resentment, self-deception, and everyday habits that can shape a person’s character.

Screwtape is a senior tempter and Wormwood is his inexperienced nephew. The human subject of their correspondence is usually called “the Patient,” rather than being given a personal name. This keeps the focus on general spiritual and psychological patterns.

Although the book uses fantasy and satire, it is not part of The Chronicles of Narnia. It is a Christian apologetic work written for adults. Lewis later said that the demonic viewpoint was difficult to sustain because it required imagining a consistently distorted moral perspective.