C.S. Lewis was the speaker in the BBC broadcasts later collected as Mere Christianity.
Lewis delivered a series of radio talks for the BBC during the Second World War. The broadcasts were intended to explain basic Christian ideas in language accessible to a broad audience, rather than to promote one particular denomination.
The talks were later revised and published in book form as Mere Christianity. The title was not the name of the original radio series; it refers to the shared core of Christian belief that Lewis sought to present across denominational boundaries.
The talks made Lewis widely known beyond academic and literary circles. His calm, argumentative style and use of everyday examples helped the broadcasts reach a large audience. A common error is to call him the producer or host in a modern television sense: his principal role was to write and deliver the talks.