This magisterial study addresses the central question in modern German history: How and why did the country embrace a racial and cultural nationalism that ultimately led to war and genocide? Smith denies that German nationalism is, as some historians argue, a single doctrine, let alone an intrinsically aggressive one. To support this thesis, Smith provides a sweeping history beginning in 1500, when Germany was an amalgam of regions, cities, and principalities. For most of the next four centuries, as Germany’s sense of cultural coherence grew, it remained a relatively peaceful region with a benign sense of national identity that neither excluded domestic minorities nor threatened external neighbors. Even in the nineteenth century, as a nationalist project to unite Germany took hold, the country remained relatively peaceful, with a few brief, if notable, exceptions, such as the Franco-Prussian War. And for the last 75 years, Germans have developed what Smith describes as a “compassionate, empathetic realism about belonging.” The “nationalist age,” from 1914 to 1945, when the politics of identity turned horribly violent, is thus an exception. Smith describes its excesses—from the slaughter on the eastern front to the Holocaust—in moving detail, but he seems, like many historians before him, somewhat baffled by their ultimate cause.