What was the title of C.S. Lewis’s collection based on his BBC radio talks about Christianity?

Mere Christianity was C.S. Lewis’s book based on his BBC radio talks about Christianity.

The talks were broadcast during the 1940s, especially during the Second World War, and were later revised and collected in book form. The title refers to the shared core of Christian belief rather than to one particular denomination.

Lewis organized the work around moral law, Christian doctrine, and the practical consequences of faith. He used accessible language and analogies, helping the book reach readers beyond academic theology. Its chapters began as spoken broadcasts, so the prose retains a direct, conversational quality.

Mere Christianity is often grouped with Lewis’s apologetic works The Problem of Pain and Miracles, but it has a different origin. It was not initially written as a single book; it developed from a series of radio talks and later editorial revisions.