Many of the major wars of the twentieth century emerged from the ruins of previous peace settlements. French hostility to the Treaty of Frankfurt of 1871 contributed to the tense political climate that culminated in the First World War; German resentment of the Treaty of Versailles helped to create the conditions necessary for Hitler's attempt to reshape Europe by force in the Second World War. Likewise the Cold War had its roots in the outcome of the titanic Russo-German struggles of 1914-17 and 1941-5 - the former created the Bolshevik regime which signed the Treaty of Brest-Litovsk, and the latter brought the Soviet armies to the River Elbe and the Soviet leadership to the negotiating table at Yalta and Potsdam." Beyond Europe, post-1945 wars in Korea, China, the Middle East and Indochina all had their origins in failed peace settlements. Why did peace so often collapse in this period? What was the causality that led from peace to war? Drawing on a series of case studies, Matthew Hughes and Matthew S. Seligmann provide a comprehensive and cohesive study that answers the question of why peace has so often failed in the modern era. The searching analysis of the key themes of peace and war has implications for conflict resolution across the globe.