Which C.S. Lewis book grew out of his 1940 BBC broadcast talks about Christianity?

C.S. Lewis’s Mere Christianity grew out of his 1940s BBC broadcast talks about Christianity. The broadcasts were delivered during the Second World War and were intended to explain core Christian beliefs to a broad radio audience.

Lewis first gave the talks in 1941, followed by further series in 1942 and 1944. He later revised and combined the material into book form. The title Mere Christianity refers to the shared central beliefs held across many Christian traditions, rather than to one denomination.

The book is organized around themes including morality, Christian belief, and the doctrine of the Trinity. It became one of Lewis’s most widely read works of Christian apologetics.

A frequent mix-up connects the BBC talks with The Problem of Pain, another major Lewis book. The Problem of Pain was published in 1940, but Mere Christianity is the work directly developed from the broadcast series.