Which C.S. Lewis book collected his BBC wartime broadcasts about Christianity?

Mere Christianity collected C.S. Lewis's BBC wartime broadcasts about Christianity.

Lewis delivered a series of radio talks for the BBC during the Second World War, beginning in 1941. The talks were designed for a broad public audience and presented a reasoned case for shared Christian beliefs rather than focusing on one denomination.

The broadcasts were later revised and published in stages, eventually forming Mere Christianity. The book discusses morality, Christian doctrine, and the meaning of faith in accessible language. It became one of Lewis's most influential works of Christian apologetics.

The title does not mean a minimal or casual version of Christianity. “Mere” refers to the central beliefs shared across historic Christian traditions. The Problem of Pain and Miracles are also apologetic works by Lewis, but neither was the collection of the BBC talks.