Which C.S. Lewis work began as BBC broadcasts during World War II?

Mere Christianity began as C.S. Lewis’s BBC broadcasts during World War II.

Lewis delivered the first broadcast talks in 1941, followed by further series in 1942 and 1944. The talks were later revised and collected as Mere Christianity, first published in book form in 1952. The title refers to what Lewis presented as the common core shared by historic Christian traditions.

The broadcasts made Lewis widely known beyond academic and literary circles. He spoke in a direct, conversational style designed for radio listeners, discussing morality, belief, and Christian doctrine without making membership in a particular denomination the starting point.

The work is not a transcript of one uninterrupted series. Its chapters combine material from several wartime broadcast sequences, and Lewis edited the text for publication. The Screwtape Letters, another famous Lewis work, was also published during the war but did not originate as BBC broadcasts.