Mere Christianity adapts material from C.S. Lewis’s wartime radio broadcasts about basic Christian belief. The broadcasts were delivered by the BBC in three series between 1941 and 1944, and the book was published in collected form in 1952.
Lewis designed the talks for a broad audience rather than for a specialist theological readership. He discussed morality, human behavior, Christian doctrines, and the differences between ordinary moral intuition and the claims of Christianity. The phrase “mere Christianity” refers to beliefs shared across many historic Christian traditions.
The book’s chapters were adapted and revised from broadcast talks, so it is not a verbatim transcript of every radio program. Lewis’s conversational style helped make the work widely accessible, while his arguments also drew sustained attention from theologians, philosophers, and general readers.
Readers sometimes assume the title means Lewis was presenting a new denomination. He was not. The phrase identifies a common core of Christian belief, not a separate church. The book remains one of his best-known works of apologetics.