The BBC commissioned the wartime radio talks by C.S. Lewis that later became Mere Christianity. Lewis delivered the talks between 1941 and 1944 for BBC radio audiences in Britain.
The broadcasts were designed to explain basic Christian beliefs in clear, nontechnical language during the Second World War. Lewis did not originally deliver one uninterrupted book called Mere Christianity; the later volume was assembled from broadcast scripts and related material.
The title Mere Christianity refers to the shared core of belief held across many Christian traditions. Lewis organized the material around themes such as morality, Christian doctrine, and practical conduct, helping make the talks accessible to listeners who were not specialists.
The BBC connection is distinct from the title of the collected book. The talks first appeared in separate published volumes, including Broadcast Talks and Christian Behaviour, before being combined and revised as Mere Christianity in 1952.