Which C.S. Lewis work originated as BBC radio talks during World War II?

Mere Christianity originated as BBC radio talks during World War II.

Lewis delivered the talks between 1941 and 1944 at the request of James Welch, the BBC’s Director of Religious Broadcasting. The broadcasts aimed to explain basic Christian beliefs to a general audience during wartime. Lewis spoke in a direct, conversational style rather than presenting a technical academic lecture.

The talks were later revised and collected into three parts: Broadcast Talks, Christian Behaviour, and Beyond Personality. These sections were eventually combined as the book Mere Christianity, first published in 1952. The title refers to the common core of belief shared by historic Christian traditions, not to a separate denomination.

Lewis’s work is often associated with apologetics, the reasoned defense of religious belief. Mere Christianity does not attempt to settle every disagreement between Christian churches; instead, it focuses on foundational ideas such as morality, virtue, and the Christian understanding of God and Jesus.