A discussion of the organization of emergency ambulance agencies, their communications systems, and levels of training of personnel. The paper is based on data obtained from 179 grant applications sent to the Robert Wood Johnson Foundation in 1973, representing agencies that serve about two-thirds of the population of the United States. Findings include: (1) Purveyors for whom emergency service is a secondary function are gradually being phased out. (2) Nationwide standards concerning citizen access to emergency medical help, training of personnel, and communication systems, which have been developed without evaluative studies showing they are valid, are not now met by most agencies. (3) Obstacles to rapid installation of dial 911 systems are still severe, with many regions opting temporarily for alternative access systems, such as use of area code 800. However, ambulance agencies believe they could correct existing command-and-control deficiencies within a two-year period, given sufficient funding. (Abridged version of R-1551.) 36 pp. Ref.