What 1942 C.S. Lewis book presents letters from a senior demon to his nephew?

The Screwtape Letters is C.S. Lewis’s 1942 book presenting correspondence from a senior demon to his inexperienced nephew. The senior tempter, Screwtape, advises Wormwood on how to lead a human patient away from faith and virtue.

Lewis wrote the work as a satirical series of fictional letters. Instead of describing temptation from a human perspective, he reverses the viewpoint and lets demonic bureaucracy, professional jargon, and strategic advice expose ordinary moral weaknesses.

The book first appeared in serial form in the Anglican newspaper The Guardian before being published as a volume. Lewis later wrote that the demonic viewpoint was difficult to sustain because it encouraged an unhealthy interest in the devil.

The nephew’s name is Wormwood, a detail sometimes confused with the title or with the human patient, whose name is never given. The work remains one of Lewis’s most frequently adapted and discussed books, especially in Christian literary circles.