In the last twenty-five years, and especially in the last ten years, environmental history in the United States has become a recognized field with a strong core of both individual and institutional support. An increasing number of historians are specializing in it. Graduate students can now study with prominent environmental historians in Ph.D. programs at several institutions and can earn a doctorate in the field. The number of academic conferences focused on environmental studies and history have proliferated in the 1990s. Whatever the questions and orientation of study, historians who study and teach the history of the role and place of nature in human life are working in a dynamic, rapidly changing field that also continues to be connected to public concerns. The field has grown primarily because it is "useful." These questions and issues press upon environmental historians with urgency not just because they emerge out of, or impinge only upon, strategies of scholarship and careers, but because they are connected to concerns about our relationship to the physical world that sustains us all.