Which C.S. Lewis book grew out of his BBC radio broadcasts from 1941 to 1944?

Mere Christianity grew out of C.S. Lewis’s BBC radio broadcasts from 1941 to 1944.

During the Second World War, Lewis delivered a series of short radio talks explaining and defending basic Christian beliefs. The broadcasts were made for the BBC and reached a large audience in Britain, where his clear, conversational style made complex theological ideas accessible.

Lewis later revised and combined the talks into books. The resulting work, Mere Christianity, was published in book form in 1952. It discusses morality, human nature, Christian belief, and the divisions shared by different Christian traditions.

The title does not refer to a particular denomination. “Mere Christianity” means the common core of beliefs held across historic mainstream Christianity. The book is therefore different in origin from The Problem of Pain, which began as a 1940 book, and The Four Loves, published in 1960.