Which C.S. Lewis book presents a series of fictional letters from a senior demon?

The Screwtape Letters presents fictional letters from a senior demon named Screwtape.

C.S. Lewis’s satirical work was published in book form in 1942. It consists of correspondence from Screwtape, an experienced tempter, to his inexperienced nephew Wormwood. The letters discuss how to mislead a human subject, but the advice is presented from the demons’ perspective so that Lewis can expose their self-deception and moral corruption.

The book began as a series in the Anglican newspaper The Guardian during 1941. Its unusual viewpoint lets Lewis explore Christian ethics indirectly: readers infer the virtues that the demons fear from the temptations they recommend. The result is both theological writing and satire.

The work is sometimes mistaken for a conventional novel or a direct guide to demonology. It is neither. Lewis framed it as imaginative fiction, and the demonic correspondence is a literary device rather than a claim that the letters are historical documents.