The first few hours following any large-scale disaster present a complex array of organizational demands that constitute a unique managerial problem. As the disaster agent changes from tornado or hurricane to toxic chemical spill or terrorist threat so, too, does the set of responding organizations and the specific tasks they confront. Despite obvious differences in the demand structures generated by such large-scale emergencies, research studies completed during the last two decades have validated the utility of a generalized approach. Initially referred to as a dual-use orientation, the concept of Comprehensive Emergency Management (CEM)' has emerged as a partial response to a long-recognized need -improved hazard and disaster management, including emergency responses.2 Fiscal year 1984 marks the initial implementation of the Integrated Emergency Management System (IEMS) at all levels of government nationwide.3 CEM is the long-term objective, IEMS is the current implementation strategy.4 The thesis of this article is that efforts to promote IEMS, or any other disaster management tool, require explicit recognition of fundamental structural qualities that characterize emergency responses within American society. The presentation is divided into four sections: (1) the American scene; (2) who actually responds?; (3) strategies for enhancing intergovernmental coordination; and (4) implications for managing emergency responses.