In this classic Christian work Chesterton answers the evolutionary materialism theory of H.G. Wells and others. According to Wells, Christ was just a remarkable leader. However Chesterton argues that an ordinary leader could never have such a remarkable influence over so many people centuries after his life on earth. He concludes that something more than just ordinary human history was at work.

C.S. Lewis speaks very highly of the work, saying it was the tipping point in his conversion to Christianity.