C.S. Lewis published Mere Christianity in 1952.
The book grew out of radio talks Lewis gave for the BBC during the Second World War. The broadcasts were later revised and collected in separate works, including Broadcast Talks and Christian Behaviour, before being brought together as Mere Christianity.
Lewis designed the book to present shared Christian beliefs rather than defend one denomination’s distinctive doctrines. Its argument from ordinary moral experience, often called the moral argument, became one of the work’s most discussed features.
The title can cause confusion because the radio broadcasts did not originally appear under that exact book title. The familiar 1952 volume is a later assembled and edited form of the earlier broadcast material.