The field of mental health services research (MHSR) focuses on the organization, financing, and delivery of mental health services (MHS) in a cost-effective way. like health services research but with a broader scope, MHSR is concerned with issues of financing, access, effectiveness, and how limited resources can be applied to achieve the best possible outcomes as measured by successful treatment, increased function, and improved quality of life. Mental health treatment and rehabilitation require not only effective psychiatric and medical care but also a wide range of social, educational, vocational, and housing services, which makes MHS coordination highly complex. Many of the services that severely mentally ill persons need are financed and administered by various agencies in the public and private sectors, by different levels of government, and by unrelated categorical programs. Understanding how to bring these services together for individual clients in a cost-effective way constitutes a major challenge to research and professional practice.Severe mental illness imposes enormous burdens on those afflicted, their families, and the community. Although the costs of mental illness for treatment and maintenance, in lost productivity, and in disability and suffering are so great, very little is invested in understanding how to reduce these costs and to use available mental health resources to achieve the best possible outcomes for individuals and communities. Individual professional practice may be guided by evidence from research, but organized systems of care, requiring billions of dollars each year, commonly proceed on the basis of trial and error and ideological positions with little of the feedback and systematic evaluation necessary for corrective action. Bureaucratic and professional preferences reinforce patterns of care that are often insensitive to the heterogeneity of patient populations, the variability of course of illness, and the broad range of services that patients with mental disabilities require to achieve an adequate level of functioning and quality of life. Needs for MHSRFor many years it was assumed that the field of MHS delivery was too vague and unwieldy to yield systematic knowledge about cost-effective delivery of care. With Improved classification and measurement, methodological refinements, and increased availability of data on many aspects of care through a variety of Federal and State agencies, it is now easier to move the field forward in a manner useful to public policy and practice. A huge amount of information about promising forms of mental health practice, organization, and financing has been acquired that provides abundant opportunities to examine the effects of alternative programs and the most appropriate combinations of program components. Investment in MHSR has been paltry relative to the dimensions of the field and the research opportunities that exist. A small group of mental health administrators at the National Institute of Mental Health (NIMH) has nurtured a modest res...