With the centennial of the start of World War I nearly upon us, historian Max Hastings offers a lively and opinionated answer to the haunting question of how the conflict began, then provides a richly detailed description of the first months of war, covering all fronts, from the fields of France to the mountains of Serbia to the plains of Russia. In Catastrophe 1914: Europe Goes to War (Knopf, $35), Hastings disputes the idea that a series of mistakes caused the conflict, instead planting the blame squarely on Germany. He recounts how, from the beginning, all the powers suffered from a mismatch of ambition and fighting capability. And in depicting the results, he broadens the focus beyond generals and statesmen to include grunts, ambulance drivers, and the wives left behind.