Which C.S. Lewis work collects his wartime BBC radio talks on Christianity?

Mere Christianity collects C.S. Lewis’s wartime BBC radio talks on Christianity.

Lewis delivered the original broadcasts between 1941 and 1944, when Britain was at war. The talks were intended for a broad radio audience rather than a specialist theological readership. Lewis discussed morality, Christian belief, and the central ideas shared by the major historic Christian traditions.

The material was later revised and published in book form. The title refers to what Lewis regarded as the common or foundational Christianity held across denominational divisions, not to a separate church or denomination.

Some readers assume the book is a transcript of one uninterrupted lecture series. It is better understood as a revised collection developed from several broadcast series: Broadcast Talks, Christian Behaviour, and Beyond Personality. Its accessible style helped make it one of Lewis’s best-known works of Christian apologetics.