Which 1942 C.S. Lewis book presents demonic correspondence about tempting a human?

The Screwtape Letters is the 1942 C.S. Lewis book presented as correspondence from a senior demon advising a junior tempter. The senior demon, Screwtape, writes to his nephew Wormwood about how to influence a human being.

Lewis uses the fictional letters to reverse the usual moral viewpoint. Readers see ordinary human weaknesses, distractions, resentment, vanity, and self-deception described as strategies in a demonic bureaucracy. The book’s satire makes its religious and psychological arguments indirectly.

The letters first appeared in the Anglican newspaper The Guardian, with the initial installment published in May 1941. They were collected as a book in 1942. Lewis later wrote the short epilogue “Screwtape Proposes a Toast.”

The work is not a conventional narrative with a continuously described plot. Its epistolary structure means that the human subject is never named and is usually called simply “the Patient.” This format is central to the book’s comic and unsettling effect.