Which 1952 C.S. Lewis book collected material adapted from his wartime radio broadcasts?

Mere Christianity collected material adapted from C.S. Lewis’s wartime radio broadcasts.

The broadcasts were delivered for the BBC during the Second World War, beginning in 1941, when Lewis was invited to explain and defend basic Christian beliefs to a broad audience. He later revised the talks and combined them with related material in a book published in 1952.

The title refers to what Lewis called the common or central beliefs shared by historic Christian traditions, rather than to one denomination. The book is divided into sections commonly known as “Right and Wrong as a Clue to the Meaning of the Universe,” “What Christians Believe,” “Christian Behaviour,” and “Beyond Personality.” It is sometimes mistakenly described as a verbatim transcript of the broadcasts; Lewis substantially revised the material for publication.