Which C.S. Lewis book presents imagined letters from a demon to his nephew?

The Screwtape Letters is the C.S. Lewis book that presents imagined letters from a senior demon to his nephew. The senior demon, Screwtape, advises Wormwood on tempting a human being.

Lewis wrote the work as a series of fictional letters, allowing him to discuss temptation, pride, distraction, fear, and self-deception from an intentionally inverted viewpoint. The demons do not represent admirable authorities; their advice exposes destructive habits by showing how evil might encourage them.

The book first appeared in serialized form in the Anglican newspaper The Guardian in 1941. It was published as a book later that year. Lewis’s style combines satire, theology, and psychological observation, which helped the work reach readers beyond academic religious audiences.

A common mix-up is to treat Screwtape as a conventional novel with a normal narrator. Its structure is epistolary: the story and arguments unfold through correspondence rather than through ordinary scenes.