What was the title of C.S. Lewis’s 1943 book based on BBC radio talks?

C.S. Lewis’s 1943 book based on BBC radio talks was Mere Christianity. The book developed material Lewis first presented in a series of wartime broadcasts intended for a broad British audience.

Lewis did not initially deliver the complete book under that exact title. The broadcasts were organized in stages and were later revised and collected into books, including The Case for Christianity, Christian Behaviour, and Beyond Personality. These sections were eventually combined as Mere Christianity.

The work presents a case for shared Christian beliefs rather than defending one particular denomination. Its discussions include morality, human nature, Christian doctrine, and the meaning of Christian faith.

The title is sometimes mistaken for the name of the original radio series. The broadcast talks and later book are closely connected, but the familiar single-volume title emerged through the process of revision and compilation.