The period spanning the two World Wars was unquestionably the most catastrophic in Europe's history. Despite such undeniably progressive developments as the radical expansion of women's suffrage and rising health standards, the era was dominated by political violence and chronic instability. Its symbols were Verdun, Guernica, and Auschwitz. By the end of this dark period, tens of millions of Europeans had been killed and more still had been displaced and permanently traumatized. If the nineteenth century gave Europeans cause to regard the future with a sense of optimism, the early twentieth...