This chapter reviews the literature on the social ecology of alcohol-related treatment in the United States. It begins with an examination of differences in the population characteristics of alcoholics and problem drinkers within and without alcohol treatment institutions. Recent trends in treatment populations are described. Also considered are a variety of factors that influence both entry into treatment and the distribution of clients across the treatment system, including gender, ethnicity, problem severity, social networks, client wants, gatekeeping practices among treatment providers, and referral patterns. The general applicability of the "health belief model" to treatment entry is assessed as well as the place of a number of well-known barriers to alcohol-related treatment in accounting for nonentry. The distribution of the society's alcohol-related caseload--both across alcohol-specific and other health and social service institutions--is considered. Also examined are recent trends in the social handling of alcohol-related problems, with special reference to the growing reliance on coercion in case recruitment. Finally, the review offers a number of suggestions regarding implications for further research and broad directions the evolution of American alcohol-related treatment institutions may take.