The Data Catalogue includes descriptions of federally funded national or multiple-site studies that have collected drug-related data over a series of years. It contains surveys specifically targeting drug use and its consequences; health surveys that include items about drug use; law enforcement surveys that offer information on drug offenses, drug offense sentencing, and drug use among offenders; surveys of youth behavior that contain data on drug use; and substance abuse treatment surveys that include data on treatment providers and their clients. The authors gathered available documentation and talked with the sponsors of these data sets, the organizations that collect and process the data, and as many users as possible to become familiar with the series' design, sampling, and data collection approaches. The researchers also investigated computer file construction, availability of the data for secondary analysis, and publications. The Catalogue is "user friendly" and includes a number of helpful tables that categorize elements across databases (e.g., populations studied, time periods covered by the databases, and specific drugs monitored).