What is the title of C.S. Lewis’s 1942 Christian apologetic book about a senior demon advising a junior one?

C.S. Lewis’s 1942 Christian apologetic book about a senior demon advising a junior one is The Screwtape Letters.

The book is structured as a series of letters from Screwtape, an experienced demon, to his inexperienced nephew Wormwood. Screwtape offers strategic advice about tempting a human patient, while Lewis uses the demonic viewpoint ironically to examine ordinary habits, moral weakness, distraction, pride, and spiritual self-deception.

Lewis wrote the work during the Second World War, and it first appeared in the Anglican newspaper The Guardian. The unusual format lets him discuss Christian ethics without presenting the advice as sincere instruction. Readers must reverse the demons’ recommendations to understand the moral point.

The book is sometimes grouped with Lewis’s other apologetic works, including Mere Christianity and The Problem of Pain, but its epistolary satire makes it distinctive. Screwtape is the senior demon, while Wormwood is the junior tempter assigned to the human “patient.”