Which C.S. Lewis work presents Christian ideas through letters from a senior demon?

The Screwtape Letters presents Christian ideas through fictional letters written by a senior demon.

Published in book form in 1942, the work consists of correspondence from Screwtape, an experienced tempter, to his nephew Wormwood. The letters offer advice about influencing a human “patient,” but their irony turns the demonic perspective against itself.

Lewis uses the device to examine pride, distraction, fear, social pressure, self-deception, and the habits that can weaken moral and spiritual life. Because the narrator is a demon, the book’s advice is deliberately inverted: readers are expected to recognize the errors Screwtape recommends.

The work began as a series of pieces broadcast during wartime and became one of Lewis’s most popular religious books. It is not a conventional story with a continuous plot; its structure is epistolary, meaning it is built from letters. That format allows Lewis to present short, sharply focused observations rather than a sustained narrative.