This important and accessible book surveys the history and present condition of river systems across the United States, showing how human activities have impoverished our rivers and impaired the connections between river worlds and other ecosystems. Ellen Wohl begins by introducing the basic physical, chemical, and biological processes operating in rivers. She then addresses changes in rivers resulting from settlement and expansion, describes the growth of federal involvement in managing rivers, and examines the recent efforts to rehabilitate and conserve river ecosystems. In each chapter she focuses on a specific regional case study and describes what happens to a particular river organism-a bird, North America's largest salamander, the paddlefish, and the American alligator-when people interfere with natural processes.