During the twentieth century, the Tigris and Euphrates rivers underwent a profound physical transformation, one that mirrored the region's political shift from imperial rule to nation-state. Here, Iraq, Syria, and Turkey took shape in the wake of the Ottoman Empire, and the two rivers became sites of economic development planning and large-scale environmental engineering. It is a modern conceit that industrial, technological societies transcend ecological change, that technology and ecology operate separately. With this book, Dale J. Stahl instead centers riverine ecologies within the context of social and political projects and shows how natural processes encounter human intentions to manage, control, or modernize. Weaving imperial and national histories with ecological ones, Two Rivers Entangled undermines familiar accounts of the invention of states, the advance of nations, and the triumphs of technical expertise. Stahl entangles a wide range of human and nonhuman actors—knitting together the movement of engineers and bureaucrats with that of salt particles, linking the disappointment of revolutionaries to the dissolution of unreliable rock, and following the flow of water over embankments and into poetry. Ultimately, this book offers an alternative account of twentieth-century Middle Eastern history, one subject as much to ecological change as to human visions and intentions.