C.S. Lewis delivered the BBC radio talks later adapted into Mere Christianity between 1941 and 1944.
The broadcasts were created during the Second World War, when radio offered a way to reach a large audience across Britain. Lewis spoke about basic Christian beliefs rather than presenting a defense of one specific denomination. The talks were designed for listeners who might have little formal theological education.
The material was later revised and collected in book form. Mere Christianity is therefore not a transcript of a single lecture or a book written entirely before the broadcasts. Its chapters grew from several broadcast series and from subsequent editing for print.
The wartime setting matters to the work’s style and audience. Lewis used ordinary examples, analogies, and direct explanations to discuss moral law, belief, and Christian doctrine. Readers sometimes remember the book as a 1940s publication without distinguishing the separate broadcast years, which ran from 1941 through 1944.