Which BBC radio talk series by C.S. Lewis became Mere Christianity?

C.S. Lewis’s BBC radio talk series Broadcast Talks became Mere Christianity.

Lewis delivered a series of Christian talks for the BBC during the Second World War. The first broadcasts were known as Broadcast Talks and were transmitted in 1941. Later installments were called Christian Behaviour and Beyond Personality. The material was revised and collected in book form as Mere Christianity.

The finished book was published in 1952 and presents a shared core of Christian belief rather than a detailed defense of one denomination. Lewis used clear analogies and conversational language because the original material was designed for radio listeners rather than specialist theologians.

A common mix-up is to call the original broadcasts Mere Christianity. That title properly identifies the later book, while Broadcast Talks is the name associated with the first set of radio talks. Lewis’s radio work helped make him a widely recognized public Christian writer.