Which C.S. Lewis book was published in 1942 as a fictional senior demon’s advice to a junior tempter?

The C.S. Lewis book published in 1942 as advice from a senior demon to a junior tempter is The Screwtape Letters. The senior demon, Screwtape, writes letters to his nephew Wormwood about tempting a human being.

Lewis presents the book as a series of fictional letters rather than a conventional theological treatise. The reversed perspective lets him satirize pride, distraction, self-deception, and shallow moral thinking. The devils’ advice is designed to expose the habits that can pull people away from virtue and faith.

The work first appeared in Britain in book form in 1942, after parts had been published in the Anglican newspaper The Guardian. Lewis later dedicated the book to his friend and fellow Inkling Charles Williams.

The title is sometimes confused with Lewis’s other apologetic works, especially Mere Christianity and The Problem of Pain. Unlike those books, The Screwtape Letters develops its arguments through correspondence between fictional demons.