Which C.S. Lewis book presents Christianity through edited radio talks?

Mere Christianity presents C.S. Lewis’s explanation of Christianity through material developed from radio talks.

The original broadcasts were delivered by Lewis for the BBC during the Second World War, beginning in 1941. He later revised and combined the talks into books, producing the volume published as Mere Christianity in 1952.

The work is an apologetic text: it argues for central Christian beliefs and attempts to describe common ground among major Christian traditions. Lewis discusses morality, human behavior, Christian doctrine, and the meaning of faith in language intended for a broad audience rather than only for academic theologians.

Readers sometimes assume the book is a transcript of one uninterrupted broadcast series. In fact, its final form was assembled from several wartime broadcast series and revised for print. The title refers to the shared core of Christianity, not to a separate denomination.