Which C.S. Lewis work presents Christianity through a series of radio talks?

Mere Christianity presents Christianity through ideas developed from C.S. Lewis’s radio talks.

The book grew out of three BBC radio series broadcast during the Second World War: Broadcast Talks in 1942, Christian Behaviour in 1943, and Beyond Personality in 1944. Lewis aimed to explain shared Christian beliefs in accessible language rather than defend one particular denomination.

The material was later revised and collected as Mere Christianity, first published in book form in 1952. Its opening discussion begins with the idea of a moral law and the human tendency to argue about whether someone has behaved rightly or wrongly.

The title does not mean Christianity is being treated as unimportant. “Mere” refers to the core beliefs held in common by many Christian traditions. The book is therefore distinct from The Problem of Pain, which focuses more directly on suffering and faith.