Which C.S. Lewis book presents a dialogue between a senior and junior demon?

The Screwtape Letters presents a dialogue through letters from the senior demon Screwtape to his junior nephew, Wormwood. C.S. Lewis uses the correspondence to satirize temptation and human self-deception.

Screwtape advises Wormwood on how to undermine a human called “the Patient.” The letters reverse the usual perspective of Christian moral writing: readers see spiritual life from the imagined viewpoint of demons trying to obstruct it.

The work first appeared in serial form in the Anglican newspaper The Guardian during 1941. It was later published as a book. Lewis’s introduction and concluding material frame the letters as a fictional device rather than a literal account of demonic communication.

The book is often grouped with Lewis’s Christian apologetics, but its method is notably dramatic and satirical. It is not a conventional theological treatise or a collection of sermons; its central structure is the exchange between Screwtape and Wormwood.