What was the title of C.S. Lewis’s 1952 book developed from BBC radio talks?

C.S. Lewis’s 1952 book developed from BBC radio talks was Mere Christianity.

Lewis delivered the original broadcasts during the Second World War, beginning with talks in 1941. He later revised and expanded the material into a book intended to explain the shared core of Christian belief rather than defend one denomination’s distinctive practices.

The published work is arranged in four parts: “Right and Wrong as a Clue to the Meaning of the Universe,” “What Christians Believe,” “Christian Behaviour,” and “Beyond Personality.” Its title refers to what Lewis viewed as basic Christianity held in common across major traditions.

The book is often confused with The Problem of Pain, another major work of Lewis’s Christian apologetics. The Problem of Pain was published in 1940 and addresses suffering, while Mere Christianity grew directly out of wartime radio broadcasts. Both books helped make Lewis a widely read twentieth-century Christian writer.