The First World War created the modern world. It destroyed a century of relative peace and prosperity and saw a continent at the height of its success descend into slaughter. It unleashed both the demons of the twentieth century - political hatred, military destruction and mass death - and the ideas which continue to shape our world today: mdoernism in the arts, new approaches to psychology and medecine, and radical ideas about economics and society. John Keegan's definitive account unforgettably portrays the unfolding military conflict on land, sea and in the air. But at its heart, too, is the terrible cost of this conflict's fercity - the loss which remains personal and individual despite its unparalleled scale.