Which C.S. Lewis book presents conversations between a demon and his nephew?

The Screwtape Letters presents fictional conversations between the senior demon Screwtape and his nephew Wormwood.

C.S. Lewis wrote the book as a series of letters from Screwtape, an experienced tempter, to Wormwood, a junior demon assigned to influence a human patient. The letters reverse ordinary moral language: demonic advice praises distraction, vanity, resentment, and self-deception while treating virtue as a threat.

The work first appeared as a newspaper serial in the Anglican periodical The Guardian in 1941. It was published in book form later that year. Lewis’s satirical format allowed him to examine ordinary temptations without presenting the discussion as a conventional theological treatise.

The book is sometimes mistaken for a straightforward handbook of Christian doctrine. It is instead a work of imaginative satire, and the demonic narrator is intentionally unreliable. Screwtape writes to Wormwood, not to the human being whom Wormwood is trying to tempt.