What title was given to C.S. Lewis’s BBC talks on Christianity when published as a book?

C.S. Lewis’s BBC talks on Christianity were published as Mere Christianity.

Lewis delivered a series of religious broadcasts for the BBC during the Second World War, beginning in 1941. The talks were intended to explain basic Christian beliefs in language accessible to a broad radio audience rather than to members of one particular denomination.

The material was later revised and collected in book form. Mere Christianity is arranged in four broad sections: “Right and Wrong as a Clue to the Meaning of the Universe,” “What Christians Believe,” “Christian Behaviour,” and “Beyond Personality: Or First Steps in the Doctrine of the Trinity.”

The title refers to the shared core of Christian belief that Lewis wanted to discuss across denominational boundaries. It is not the title of the original broadcast series itself; the talks appeared under separate broadcast titles before being collected. That publishing history explains why readers sometimes treat the book and the radio programs as identical editions.