What was the name of the radio talks that became C.S. Lewis’s Mere Christianity?

The radio talks that became C.S. Lewis’s Mere Christianity were broadcast talks.

Lewis first presented the ideas behind Mere Christianity in a series of BBC radio talks broadcast during the 1940s. The talks were later revised and published in book form, with the title Mere Christianity referring to the shared core of Christian belief rather than to one denomination.

The first group was broadcast in 1941 under the title Broadcast Talks. Later groups were titled Christian Behaviour and Beyond Personality. These materials were subsequently combined and revised for publication as Mere Christianity, first issued in book form in 1952.

A common mix-up is to treat Mere Christianity as the original broadcast title. It was the later book title. Lewis’s purpose was not to present a complete account of every Christian doctrine, but to explain what he regarded as central beliefs held across major Christian traditions.