The outbreak of World War I was greeted with widespread European enthusiasm. For decades, Europe’s Great Powers had been divided into alliance blocs in anticipation of a conflict. The currents of extreme nationalism, competition for overseas colonies, and Social Darwinism that characterized the prewar era convinced many that war was not only inevitable, but desirable—a brief, decisive test of “survival of the fittest.” In reality, the conflict was a long, brutal contest in which the combatants had to mobilize all of their resources—people, raw materials, transportation infrastructure, and factories—in a “total war” that made little distinction between soldiers and civilians. In the trenches on the western front, the war stagnated into a contest of attrition. In the east, the collapse of the Russian Empire paved the way for the eventual Soviet state, but did not lead to a German victory. In the end, the human and economic costs of the war dwarfed all previous conflicts. Despite this, and despite the efforts of U.S. President Woodrow Wilson to use the subsequent peace negotiations to forge a new, more peaceful international order, the world emerged from global war in 1919 as divided and unstable as ever. Within two decades, a new round of conflict in Europe would spark a second world war, this one even more destructive than the first. ■