Which C.S. Lewis work was based on BBC radio broadcasts?

C.S. Lewis’s Mere Christianity was based on BBC radio broadcasts. Lewis delivered the talks during the Second World War, beginning in 1941, and later revised them into the book published in 1952.

The broadcasts were intended for a broad British audience rather than a specialist theological readership. Lewis presented arguments about morality, human behavior, and Christian belief in accessible language, avoiding the detailed treatment associated with an academic theology textbook.

The book is arranged in four parts: “Right and Wrong as a Clue to the Meaning of the Universe,” “What Christians Believe,” “Christian Behaviour,” and “Beyond Personality.” The final section discusses the Christian doctrine of the Trinity.

Mere Christianity became one of Lewis’s most influential works of Christian apologetics. It is not a denominational confession; its title refers to core beliefs shared across many Christian traditions.