Which C.S. Lewis book presents a series of letters from a senior demon advising a junior tempter?

The Screwtape Letters presents a series of letters from a senior demon advising a junior tempter.

C.S. Lewis’s The Screwtape Letters was published in book form in 1942. Its narrator, Screwtape, is an experienced demon who writes to his inexperienced nephew Wormwood about tempting a human being. Lewis reverses the usual moral viewpoint: readers hear demonic advice and infer the spiritual dangers it describes.

The letters originally appeared in a British newspaper during the Second World War before being collected as a book. Lewis used satire to examine distraction, pride, resentment, self-deception, and the gradual formation of habits.

The book is not a conventional story with a continuous external narrator. Its epistolary structure—letters exchanged between two demons—creates the central comic device. The sequel-like work Screwtape Proposes a Toast was published later as a separate piece, so it should not be confused with the original collection.