Which C.S. Lewis book collects his BBC talks on basic Christian belief?

Mere Christianity collects C.S. Lewis’s BBC talks on basic Christian belief.

Lewis delivered the original radio broadcasts during the Second World War, beginning with the series Broadcast Talks in 1941. Further broadcasts followed in 1942 and 1944. Walter Hooper later described the collected work as a book assembled from these talks and related material.

The title refers to the shared core of Christian belief rather than to one denomination. Lewis discusses morality, human behavior, repentance, Christian virtues, and the doctrine of the Trinity in a style intended for a broad radio audience.

The book is sometimes confused with The Problem of Pain, which is a separate 1940 work focused on suffering and the problem of evil. Mere Christianity became one of Lewis’s most influential Christian apologetics books and helped establish his public reputation as a religious broadcaster.