Which C.S. Lewis book retells the Christian story through a fictional correspondence between demons?

The Screwtape Letters retells the Christian story through fictional correspondence between demons.

Published in book form in 1942, The Screwtape Letters consists of letters from Screwtape, a senior demon, to his inexperienced nephew Wormwood. Screwtape advises Wormwood on how to tempt a human subject away from Christian faith and moral awareness. Lewis uses the reversed perspective to satirize demonic reasoning and expose habits such as vanity, distraction, resentment, and self-deception.

The work first appeared as a series of letters in The Guardian, an Anglican newspaper, during 1941. Lewis later dedicated it to his friend J.R.R. Tolkien, although their friendship was not always free from disagreement.

The book is sometimes confused with The Great Divorce, another imaginative work about the afterlife. The Great Divorce uses a traveller’s journey and conversations, whereas The Screwtape Letters is built around correspondence from the infernal bureaucracy.