The First World War created the modern world. A conflict of unparalleled ferocity which extended far beyond its European epicentre, it broke the century of relative peace and prosperity which we associate with the Victorian era and unleashed the demons of the twentieth century - pestilence, military destruction and mass death - and also the ideas which continue to shape our world today - modernism in the arts, new approaches to psychology and medicine, and radical ideas about economics and society. It was of course foremost a military conflict, and the battles on land, sea and in the air form the narrative heart of his study, with some fascinating new interpretations of the military events. But the war also acted as a formidable engine for change throughout the world, and this too is revealed in his new book. At its heart, however is the terrible human cost of this unparalleled conflict, the loss which, however vastly extended, remains personal and individual.