What was C.S. Lewis’s wartime radio-talk book called?

C.S. Lewis’s wartime radio-talk book was Mere Christianity. The book grew from talks broadcast by the BBC during the Second World War and was later assembled into a unified work of Christian apologetics.

Lewis first delivered the broadcasts between 1941 and 1944. He aimed to explain basic Christian beliefs in language accessible to a broad radio audience, rather than defend the distinctive doctrines of one denomination. The finished book is divided into sections concerning right and wrong, Christian belief, Christian behavior, and personality.

The title does not mean that Lewis considered all Christian differences unimportant. Instead, “mere Christianity” refers to the central beliefs shared across much of historic Christianity. The radio talks were also not delivered as one continuous series under exactly the same later book structure, which is why publication history can seem complicated.