What was the original medium of C.S. Lewis’s Mere Christianity?

Mere Christianity began as BBC radio broadcasts by C.S. Lewis. The talks were delivered during the Second World War, first in 1941 and later in 1942 and 1944, to explain basic Christian ideas to a broad public audience.

Lewis’s broadcasts were not initially issued as one finished book. He later revised and expanded the material for print. The resulting volume, Mere Christianity, was published in 1952 and became one of his best-known works of Christian apologetics.

The title refers to what Lewis presented as central Christian belief shared across major traditions, rather than the distinctive teachings of one denomination. His argument often proceeds through moral experience, reason, and examples from ordinary life. The work is therefore neither a memoir nor a novel.

A related confusion concerns The Problem of Pain, another major Lewis book. That work was published in 1940 and was written as a book from the outset. Mere Christianity’s defining origin was its wartime radio talks, which gave Lewis an unusually large general audience.