'Mere Christianity', CS Lewis's classic of Christian apologetics, adapted from a series of BBC radio talks made between 1941 and 1944 while Lewis was at Oxford. The work was originally published as three separate pamphlets: The Case for Christianity (1942), Christian Behaviour (1943) and Beyond Personality (1944). Lewis focuses on the common ground in the Christian faith to explain the fundamental teachings of Christianity, in order to make a powerful and rational case for the faith. As one of the most popular introductions to Christianity ever published, 'Mere Christianity' has sold millions of copies worldwide.