Which C.S. Lewis work is an epistolary satire narrated by a senior demon?

The Screwtape Letters is an epistolary satire narrated through advice from the senior demon Screwtape. The letters are addressed to Wormwood, a junior tempter assigned to influence a human being.

Lewis uses the demonic viewpoint to examine temptation, pride, distraction, resentment, and spiritual complacency. Because the narrator is deliberately unreliable and morally inverted, the book’s observations are expressed as advice about how to lead people away from goodness.

The work first appeared in serialized form in the Anglican newspaper The Guardian in 1941 and was published as a book in the same year. Lewis later dedicated it to his friend J.R.R. Tolkien, although the dedication was removed from some editions.