Which 1942 book by C.S. Lewis presents correspondence between a senior demon and his apprentice?

The Screwtape Letters is C.S. Lewis’s 1942 book of fictional correspondence between a senior demon and his apprentice.

The senior demon, Screwtape, writes advice to his inexperienced nephew Wormwood about tempting a human being. Lewis uses the reversed perspective to satirize self-deception, distraction, pride, and other moral weaknesses.

The work was first published in book form in 1942 by Geoffrey Bles. Its letters had originally appeared in the Anglican newspaper The Guardian, where Lewis’s Christian apologetic writing reached a broad audience during the Second World War.

The book is not a conventional novel with a continuous narrative told by a human narrator. Its epistolary structure is the main literary device, and the demonic voice is deliberately ironic. That format is why it is often cited as one of Lewis’s most inventive works alongside his more straightforward apologetic books.