What title did C.S. Lewis give the book developed from his wartime radio talks?

C.S. Lewis gave the book developed from his wartime radio talks the title Mere Christianity.

The BBC broadcast Lewis’s talks during the Second World War, beginning in 1941. He aimed to explain basic Christian ideas in accessible language to a broad radio audience rather than argue for one particular denomination. The talks were later revised and collected in book form.

Mere Christianity was published in 1952. Its sections discuss morality, Christian belief, and the virtues of Christian life. The phrase “mere Christianity” refers to the core beliefs shared across historic Christian traditions, not to a separate church or denomination.

The book helped establish Lewis as a prominent Christian writer and public intellectual. It is sometimes mistaken for a transcript of untouched broadcasts, but Lewis edited and reorganized the material for publication. The work’s opening moral argument and discussion of the Christian doctrine of the Trinity remain especially frequently quoted portions.