What is the name of C.S. Lewis’s 1942 Christian satire featuring a senior demon’s letters?

C.S. Lewis’s 1942 Christian satire featuring a senior demon’s letters is The Screwtape Letters.

The book consists of correspondence from Screwtape, an experienced demon, to his inexperienced nephew Wormwood. Screwtape offers advice about tempting a human patient, while Lewis presents the advice ironically so that readers can recognize the moral and spiritual errors being described. The letters first appeared in the Anglican newspaper The Guardian in 1941 and were collected as a book in 1942.

Lewis dedicated the work to J.R.R. Tolkien, though the two friends had different literary approaches. The book is not a conventional narrative with a continuous plot; its structure is a series of imagined letters. Readers sometimes confuse its demons with characters from The Chronicles of Narnia, but The Screwtape Letters is an adult-oriented work of Christian apologetics and satire rather than children’s fantasy.