Which C.S. Lewis book presents Christianity through conversations broadcast on British radio?

Mere Christianity presents C.S. Lewis’s explanation of core Christian beliefs through material first delivered in British radio broadcasts. The talks were recorded during the Second World War and later revised into book form.

The original broadcasts began in 1941, when Lewis was invited by James Welch of the BBC to speak about Christianity to a broad audience. Lewis’s conversational style helped make the talks accessible to listeners who were not specialist theologians.

The book’s title refers to what Lewis called “mere Christianity”: beliefs shared by many historic Christian traditions, rather than the distinctive doctrines of one denomination. The finished volume was published in 1952.

The work is sometimes mistaken for a transcript of uninterrupted live lectures. In fact, the radio talks appeared in several series and were edited and expanded for publication. Mere Christianity remains one of Lewis’s most widely read apologetic works.