Which C.S. Lewis book presents arguments based on his wartime BBC radio talks?

Mere Christianity presents arguments based on C.S. Lewis’s wartime BBC radio talks.

Lewis delivered the first series of talks in 1941, followed by further broadcasts in 1942 and 1944. He spoke to a British public living through the Second World War and aimed to explain shared Christian ideas in accessible language rather than defend one particular denomination.

The broadcasts were later revised and collected as Mere Christianity. The book was published in 1952 and became one of Lewis’s most influential works of Christian apologetics. Its opening arguments about morality, human behavior, and religious belief are especially widely quoted.

The title does not refer to a separate church or denomination. “Mere Christianity” means the common core of belief Lewis saw across historic Christian traditions. The Problem of Pain and Miracles are related apologetic works, but they were not the book assembled from these radio talks.