Which C.S. Lewis work grew out of BBC radio broadcasts from 1941 to 1944?

Mere Christianity grew out of C.S. Lewis’s BBC radio broadcasts from 1941 to 1944.

The broadcasts were delivered during the Second World War and aimed to explain basic Christian beliefs in language accessible to a broad British audience. Lewis was already known as an Oxford literary scholar, but the talks made him widely recognized as a Christian communicator.

The material was later revised and published in book form. Mere Christianity is arranged around a general moral argument, central Christian beliefs, and the virtues Lewis considered important in Christian life. The title refers to the shared core of belief that Lewis believed united many Christian traditions.

It was not originally written as a single book from the beginning. Its broadcast origins explain the direct, conversational style and the way the final volume brings together material from several series of talks.