Which C.S. Lewis book collects material from his BBC broadcasts about basic Christian beliefs?

Mere Christianity collects C.S. Lewis’s BBC broadcasts about basic Christian beliefs.

The broadcasts were delivered during the Second World War, beginning in 1941, and were intended for a general audience rather than a specialist theological readership. Lewis explained ideas such as morality, repentance, and Christian doctrine in direct, conversational language.

The material was later revised and published in book form. The title refers to what Lewis regarded as the common ground shared by major Christian traditions, rather than to a separate denomination or church.

Mere Christianity is often confused with The Case for Christianity, an earlier collection of some broadcast material. The final book is arranged into four sections: “Right and Wrong as a Clue to the Meaning of the Universe,” “What Christians Believe,” “Christian Behaviour,” and “Beyond Personality.”