Which BBC radio talks by C.S. Lewis were later revised into Mere Christianity?

C.S. Lewis’s Broadcast Talks were later revised into Mere Christianity.

Lewis delivered the talks for the BBC during the Second World War, beginning in 1941. The broadcasts were aimed at a general audience and explained central Christian ideas in accessible language. They were later revised and expanded into three sections: The Case for Christianity, Christian Behaviour, and Beyond Personality.

The combined book appeared as Mere Christianity in 1952. Lewis did not originally broadcast a finished book under that title; the title came from the later printed collection. The phrase refers to the shared core of Christian belief rather than to a separate church denomination.

The talks helped establish Lewis as a prominent public Christian writer in Britain. His clear style, examples, and logical structure made the broadcasts influential far beyond their wartime setting. They are sometimes confused with The Four Loves, which also developed from BBC material, but The Four Loves concerned categories of love and was published separately in 1960.