Which C.S. Lewis book presents Christianity through four radio-talk series?

Mere Christianity presents Christianity through four radio-talk series by C.S. Lewis.

The talks were broadcast by the BBC during the Second World War, beginning in 1941. Lewis aimed to explain basic Christian beliefs in language accessible to a general British audience, rather than argue for one particular denomination. He later revised and combined the broadcasts into book form.

The final book, Mere Christianity, is organized into four sections: “Right and Wrong as a Clue to the Meaning of the Universe,” “What Christians Believe,” “Christian Behaviour,” and “Beyond Personality.” Its title refers to the shared core of belief that Lewis believed united historic Christian traditions.

The work is sometimes described as a single radio program, but it developed through multiple broadcast series. It is also distinct from The Problem of Pain, which Lewis published in 1940 as a focused discussion of suffering and divine goodness. Mere Christianity became one of his most influential apologetic books.