In the mid-nineteenth century, most Progressive Era conservation policies would have been considered unconstitutional. Smith traces how, between 1870 and 1930, the conservation movement reshaped constitutional doctrine to its purpose--how, specifically, courts and lawyers worked to expand government authority to manage wildlife, forest and water resources, and pollution. Her work, which highlights a number of important Supreme Court decisions often overlooked in accounts of this period, brings the history of environmental management more fully into the story of the US Constitution. At the same time, illuminating the doctrinal innovation in the Progressives' efforts, her book reveals the significance of constitutional history to an understanding of the government's role in environmental management.