Four separate human services programs and their West Philadelphia service consumers were studied by the 1971 Health Network Project: a hospital receiving ward, a community mental health satellite center, a public assistance district office, and a public child welfare agency. The basic hypotheses were that 1) the four consumer groups present common health, economic, and social problems, and 2) each agency confines its services to its own specialized range of problems and provides minimal linkages to other service facilities, including those available within its own subdivisions. Data were obtained by interview and record review from over 600 patients and clients. Each agency was found to respond to presenting problems with specific interventions. However, failure to detect, treat, or refer concurrent problems was pronounced. Despite the great prevalence of physical and mental illness, compounded by economic marginality, each agency made minimal use of internal support services and external referrals. The human services nonsystem is discussed conceptually in light of specialization and fragmentation. Proposals for shifting the nonsystem toward a responsive service network include the introduction of comprehensive screening devices and of service generalists for case management.