The study of streams and rivers combines ecology, chemistry, hydrology, and geology to reveal the factors that control the biological diversity and functioning of these unique ecosystems. Although stream ecology is a relatively young discipline, foundational papers published over the past half century have shaped our current understanding of these ecosystems and have informed our efforts to manage and protect them. Organized by topics such as the physical template, community structure, food webs, ecosystem energetics, and nutrient dynamics, the chapters of this book offer summaries of the key literature, historical and contextual information, and insightful discussions of how past research has influenced present studies and may shape future work.