What was the original medium of C.S. Lewis’s talks later collected as Mere Christianity?

The material later collected as Mere Christianity began as BBC radio broadcasts.

During the Second World War, Lewis delivered a series of short talks for BBC Radio. The first series, Broadcast Talks, aired in 1941, followed by Christian Behaviour in 1942 and Beyond Personality in 1944. Lewis wrote and delivered the talks for a general audience rather than a specialist theological readership.

The broadcasts explained shared Christian beliefs and moral ideas in plain, conversational language. Dorothy L. Sayers helped with some of the broadcast scripts’ presentation, while the BBC later gathered the material into book form. The combined volume was published as Mere Christianity in 1952.

The title refers to the basic beliefs common to many Christian traditions, not to a separate denomination. The book’s radio origins help explain its accessible style, short sections, and frequent use of everyday examples. It remains one of Lewis’s most widely read works of Christian apologetics.