Which C.S. Lewis work presents Christianity through adapted wartime radio talks?

Mere Christianity presents C.S. Lewis’s explanation of Christianity through material adapted from wartime radio talks. The book developed from broadcasts Lewis delivered for the BBC between 1941 and 1944.

The talks were intended for a broad British audience during the Second World War. Lewis discussed morality, belief, Christian doctrines, and the differences between major Christian traditions. He aimed to explain what he called “mere Christianity”: beliefs shared by many Christians rather than the distinctive teachings of one denomination.

The broadcasts were later collected and revised into separate books, including Broadcast Talks and Christian Behaviour. The combined volume titled Mere Christianity appeared in 1952.

The work is not a novel and is not a formal systematic theology textbook. Its conversational style helped make Lewis one of the best-known Christian apologists of the twentieth century. The phrase “mere Christianity” became closely associated with his approach to shared Christian belief.