C.S. Lewis’s book Mere Christianity presents the idea that Christians of different denominations share a central body of beliefs. The work developed from radio broadcasts Lewis gave during the Second World War and was published as a book in 1952.
Lewis uses “mere Christianity” to mean the common ground of historic Christian belief rather than the distinctive practices of one denomination. He discusses moral law, human wrongdoing, Christian doctrine, and the practical consequences of faith.
The book is organized into four parts: “Right and Wrong as a Clue to the Meaning of the Universe,” “What Christians Believe,” “Christian Behaviour,” and “Beyond Personality.” Its accessible style helped make Lewis one of the best-known Christian apologists of the twentieth century.
Mere Christianity is often confused with Lewis’s earlier apologetic works, especially The Problem of Pain and Miracles. Unlike those books, it grew directly out of a sequence of wartime broadcasts and was designed for a broad general audience.