Which 1941 BBC talks by C.S. Lewis later formed the basis of Mere Christianity?

C.S. Lewis’s 1941 BBC talks were called Broadcast Talks and later formed the foundation of Mere Christianity. The first series was transmitted during the Second World War for a British radio audience.

Lewis was invited to explain Christian belief in accessible language rather than to deliver academic lectures. The talks addressed morality, belief, and the common ground among historic Christian traditions. Their conversational style helped make difficult ideas available to listeners who were not specialists.

The material was revised and expanded through later BBC series. Broadcast Talks was followed by Christian Behaviour in 1942 and Beyond Personality in 1944. These texts were eventually brought together, with revisions, as Mere Christianity.

A frequent mistake is to give one of the later section titles as the name of the original 1941 series. Broadcast Talks specifically identifies the first set, while Mere Christianity is the later book title for the collected and developed material.