What Christian radio book grew from C.S. Lewis’s BBC broadcasts during World War II?

Mere Christianity grew from C.S. Lewis’s BBC broadcasts during World War II.

Lewis delivered a series of radio talks for the BBC between 1941 and 1944. The broadcasts addressed basic Christian beliefs in language intended for a broad listening audience rather than for a specialized theological readership.

After revision, the talks appeared in book form as Mere Christianity. The title refers to the shared core of belief among major Christian traditions, not to a separate denomination. Lewis organized the work around morality, Christian belief, and practical Christian conduct.

The book is often grouped with Lewis’s apologetic works, including The Problem of Pain. It is distinct from The Screwtape Letters, a fictional work presented through imagined correspondence between demons.