Book excerpt: Describes and maps the North American oceanic and coastal waters, classifying them into 24 marine ecoregions, according to oceanographic features and geographically distinct assemblages of species. Descriptive profiles of the ecoregions describe their key features, in terms of physical, oceanographic, and biological characteristics, as well as human impacts. The book is intended to provide a framework for collecting and organizing information on these regions, and to encourage a sense of joint responsibility and a collaborative strategic approach to dealing with the challenges of conserving the regions' shared oceans.