The articles in this special section of the Journal of Behavioral Health Services & Research (30:1) present results from evaluations of publicly funded managed care initiatives for substance abuse and mental health treatment in Arizona, Iowa, Maryland, and Nebraska. This overview outlines the four managed care programs and summarizes the results from the studies. The evaluations used administrative data and suggest a continuing challenge to structure plans so that undesired deleterious effects associated with adverse selection are minimized. Successful plans balanced risk with limited revenues so that they permitted greater access to less intensive services. Shifts from inpatient services to outpatient care were noted in most states. Future evaluations might conduct patient interviews to examine the effectiveness and quality of services for mental health and substance abuse problems more closely.