What was the title of C.S. Lewis’s BBC-based Christian book?

C.S. Lewis’s BBC-based Christian book is Mere Christianity. The work developed from radio talks Lewis delivered for the BBC during the Second World War, especially between 1941 and 1944.

Lewis aimed to present shared Christian beliefs rather than defend one denomination’s distinctive doctrines. The broadcasts were later revised and collected in book form. Its sections discuss morality, Christian belief, and practical implications of faith, using a conversational style intended for a broad audience.

The title refers to what Lewis called “mere Christianity,” meaning the central beliefs held across historic Christian traditions. The book is not a transcript of a single broadcast series in its final form; Lewis edited and reorganized the material for publication. It became one of his most influential works of Christian apologetics.