What was the title of C.S. Lewis’s 1950 book about Christian belief based on radio talks?

Mere Christianity was C.S. Lewis’s 1950 book based on radio talks about Christian belief.

The book developed from broadcasts Lewis gave for the BBC during the Second World War. The talks were intended for a broad public audience, including listeners who were uncertain about Christianity. Lewis organized the material around shared principles rather than the distinctive doctrines of one denomination.

The title refers to what Lewis considered the common or central beliefs held across historic Christian traditions. The book discusses morality, belief, Christian conduct, and the doctrine of the Trinity. Its conversational origins helped make the prose accessible to readers beyond academic theology.

Mere Christianity is sometimes confused with The Problem of Pain, another Lewis book about faith and suffering, or with Miracles, which examines the supernatural. Neither of those books was assembled from the same BBC broadcast series.