C.S. Lewis’s Mere Christianity radio talks first began broadcasting in 1941. The BBC invited Lewis to speak during the Second World War, when radio offered a way to reach a large civilian audience.
The talks explained basic Christian ideas in accessible language rather than presenting a detailed defense of one denomination. Lewis drew on themes such as morality, repentance, belief, and the nature of God. His calm, conversational style helped make the broadcasts widely noticed.
The talks were later revised and published in book form. Mere Christianity became one of Lewis’s most influential works of Christian apologetics, although the title was not the original title of a single broadcast series. The book combines material from several sets of wartime talks.
The work is sometimes mistaken for a novel or a formal church catechism. It is better described as a popular explanation and defense of shared Christian beliefs, written for a broad audience.