What was the name of C.S. Lewis’s BBC radio talks later collected as Mere Christianity?

The BBC radio talks later collected as Mere Christianity were first called Broadcast Talks.

Lewis delivered the talks during World War II, beginning in 1941. They were intended for a broad British audience and explained basic Christian ideas in clear, conversational language. The broadcasts made Lewis widely known beyond academic and literary circles.

The talks were later revised and published in book form. The first series became The Case for Christianity, the second became Christian Behaviour, and the third became Beyond Personality. These sections were eventually combined as Mere Christianity in 1952.

The title Mere Christianity refers to the shared core of belief held across many historic Christian traditions. Lewis did not present the book as a complete denominational theology. The work is therefore both a radio-broadcast project and a later book, with several titles associated with different stages of publication.