Territorial boundaries, as Maier writes, are what “transforms geography into history.” In this brilliant and sweeping narrative, Maier shows how, beginning in the seventeenth century, sovereignty and territory became intertwined as states built borders, reorganized systems of labor and capital, and forged domains of law and authority. In the nineteenth century, the Industrial Revolution and the development of the railroad, the steamship, and the telegraph allowed modern states to organize and control ever-larger expanses of territory. Territory soon became increasingly tied to geopolitics, as the rise and fall of great powers depended on their grand imperial projects, whose goal was to control large landmasses. The book goes on to trace how the Cold War led to the territorialization of ideology and to examine shifts in the scientific and philosophical conceptions of space. Maier finds today’s world awash in fast-changing and deeply conflicting ideas about territory. The interdependence of economies and the emergence of cyberspace seem to have reduced the salience of physical territorial control and weakened traditional notions of sovereignty and citizenship. But if Maier is correct, territory will continue to claim an important place in the human imagination.