Mere Christianity is a theological book by C. S. Lewis, adapted from a series of BBC radio talks made between 1941 and 1944,[2] while Lewis was at Oxford during the Second World War.[3] Considered a classic of Christian apologetics, the transcripts of the broadcasts originally appeared in print as three separate pamphlets: The Case for Christianity (Broadcast Talks in the UK) (1942), Christian Behaviour (1943), and Beyond Personality (1944).[4] Lewis was invited to give the talks by the Reverend James Welch, the BBC Director of Religious Broadcasting, who had read his 1940 book, The Problem of Pain.