Law enforcement officials know the devastation that drinking can cause among the immature and the inexperienced. This guide is intended to be used by law enforcement agencies in cooperation with other segments of the community. It provides an overview of the problem of youth access to alcohol, a discussion of the legal and policy issues relating to enforcement of alcohol access laws, and a description of some enforcement strategies and tools. The material contained here should demonstrate to community leaders that the presence and activism of police officers and other enforcement officials are important parts of any effort to prevent underage drinking. The information is presented in three sections: alcohol in the community, minimum purchase age, and drinking and driving enforcement. Included are discussions of legal and policy structures, enforcement techniques, enforcement aimed to prevent youth access, barriers to drinking and driving enforcement, assessing youth DWI (driving while intoxicated) enforcement, DWI management strategies, and policy tips on how to handle large concentrations of youth, typified by some parties, who are impaired. Some examples of successful enforcement programs and strategies, which have been used in communities across the United States conclude the guide. Contains a 10-item annotated list of resources. (RJM)