What medium first presented C.S. Lewis’s Mere Christianity to a wide audience?

Mere Christianity first reached a wide audience through C.S. Lewis’s BBC radio broadcasts. Lewis delivered talks during the Second World War, beginning in 1941, for British listeners seeking accessible discussion of Christian belief.

The broadcasts were not originally delivered as the finished book now called Mere Christianity. Lewis revised and expanded the talks, and the material was later published in book form in 1952.

The title refers to what Lewis presented as the shared core of Christianity rather than the distinctive doctrines of individual denominations. The work is arranged around themes including morality, belief, and Christian conduct.

The radio talks established Lewis as a major public religious speaker. His calm, clear style made abstract theological ideas understandable to a general audience, and the later book became one of his most widely read works. The broadcasts also helped distinguish him from purely academic writers.