Written by one of Europe's leading social theorists, this book takes up the claims of modernity and confronts them with a stark reality: the ongoing proliferation of war. How can contemporary social and political thought come to terms with this apparent failure of modernity? Throughout the 20th century the global struggle of ideologies put paid to the dream that wars were somehow the relic of a bygone, unenlightened age. But now in the aftermath of the Cold War era, how are we to account for the persistence of war and state violence? Drawing on a wide range of material, from World War I and Vietnam to the Gulf War and the conflicts in the Balkans, Joas engages with current debates in the sociology and politics of war and develops his own distinctive line of argument concerning the role of warfare in modern societies. He aligns himself with figures such as Giddens and Mann in the attempt to establish a new and non-functionalist theory of social change. This compelling and timely study confronts one of the great paradoxes of our era, and Joas's book is a substantial contribution towards a new historico-sociological perspective on the twentieth century. It will be of particular interest to students and scholars of sociology and politics, and will appeal to anyone who has puzzled over the persistence of modern war, and the limits of enlightenment as an historical force.