Which C.S. Lewis book records radio talks later adapted into Mere Christianity?

Broadcast Talks records the radio talks later adapted into Mere Christianity.

C.S. Lewis delivered a series of Christian talks on BBC radio during the Second World War. The first group was broadcast in 1941, followed by further series in 1942 and 1944. The talks were aimed at a general audience and explained basic Christian ideas without presenting one denomination’s distinctive theology as the central subject.

Lewis revised and collected the material in book form. The first collection appeared in 1952 under the title Mere Christianity, while the original broadcast material had been published in separate volumes, including Broadcast Talks. The later book became one of Lewis’s best-known works of Christian apologetics.

The radio talks are sometimes described as though Mere Christianity was originally written as a single conventional book. Its origins were spoken broadcasts, shaped for listeners during wartime Britain. That history helps explain the direct style, clear examples, and conversational structure of the final collection.