For centuries conquerors, missionaries, and political movements acting in the name of a single god, nation, or race have sought to remake human identities. Tracing the rise of exclusive forms of identity over the past 1500 years, this innovative book explores both the creation and destruction of exclusive identities, including those based on nationalism and monotheistic religion. Benjamin Lieberman focuses on two critical phases of world history: the age of holy war and conversion, and the age of nationalism and racism. His cases include the rise of Islam, the expansion of medieval Christianity, Spanish conquests in the Americas, Muslim expansion in India, settler expansion in North America, nationalist cleansing in modern Europe and Asia, and Nazi Germany's efforts to build a racial empire. He convincingly shows that efforts to transplant and expand new identities have paradoxically generated long periods of both stability and explosive violence that remade the human landscape around the world.