The three volumes of North American Exploration appraise the full scope of the exploration of the North American continent and its oceanic margins from prior to the arrival of Columbus until the end of the nineteenth century. More than an assessment of historical events, these volumes portray the process of exploration. Without forgetting the romance of discovery, the authors recognize that exploration encompasses a great deal more than the adventures themselves. All explorers are conditioned by the time, place, and circumstances of their efforts; these determine objectives, the behavior of explorers, and the consequences of their discoveries. The second volume includes the exploration of North America from the Spanish entrada of the sixteenth century to the British and Russian explorations of the Pacific coastal regions at the end of the eighteenth century—a time during which North America was largely defined and understood in terms of advancing scientific viewpoints during the European Enlightenment. Discovery gave way to Exploration and supposition to understanding.