Which C.S. Lewis book originated as BBC radio broadcasts from 1941 to 1944?

Mere Christianity originated as BBC radio broadcasts from 1941 to 1944.

Lewis first presented the material in radio talks during the Second World War. The talks were later revised and collected as Mere Christianity, a book published in 1952. The work explains central Christian beliefs in language intended for a broad audience rather than for specialists in theology.

The finished book has three major sections: “Right and Wrong as a Clue to the Meaning of the Universe,” “What Christians Believe,” and “Christian Behaviour.” A fourth section, “Beyond Personality,” discusses the Trinity and Christian spiritual life. Lewis’s aim was to describe what he regarded as common ground among historic Christian traditions, not to promote one denomination.

The title can be misunderstood as a claim that the book is merely an introduction with no argument. It includes sustained reasoning about morality, belief, pride, forgiveness, and Christian doctrine. The radio origins also explain its conversational tone and accessible structure.