In the nineteenth and twentieth centuries, a handful of powerful European states controlled more than a third of the land surface of the planet. These sprawling empires encompassed not only rainforests, deserts, and savannahs but also some of the world's most magnificent rivers, lakes, marshes, and seas. Liquid Empire tells the story of how the waters of the colonial world shaped the history of imperialism, and how this imperial past still haunts us today. Spanning the major European empires of the period, Corey Ross describes how new ideas, technologies, and institutions transformed human engagements with water and how the natural world was reshaped in the process. Water was a realm of imperial power whose control and distribution were closely bound up with colonial hierarchies and inequalities-but this vital natural resource could never be fully tamed. Ross vividly portrays the efforts of officials, engineers, fisherfolk, and farmers to exploit water, and highlights its crucial role in the making and unmaking of the colonial order. Revealing how the legacies of empire have persisted long after colonialism ebbed away, Liquid Empire provides needed historical perspective on the crises engulfing the world's waters, particularly in the Global South, where billions of people are faced with mounting water shortages, rising flood risks, and the relentless depletion of sea life.