Natural History of Drug Abusing Behaviors -- Defining and Measuring Drug Abusing Behaviors -- Drug Abuse Heterogeneity and the Search for Subtypes -- Studying the Natural History of Drug Use -- Health, Social, and Psychological Consequences of Drug Use and Abuse -- Epidemiological Methods -- Use of Archival Data -- Sampling Issues in Drug Epidemiology -- Collecting Drug Use Data from Different Populations -- Indirect Methods to Estimate Prevalence -- Qualitative Methods in the Drug Abuse Field -- Ethical Considerations for Drug Abuse Epidemiologic Research -- Descriptive and Analytic Epidemiologic Studies -- A Common Language for a Common Problem: The Developing Role of Drug Epidemiology in a Global Context -- Longitudinal Studies of Drug Use and Abuse -- Drug Abuse and the Spread of Infection: HIV and AIDS as an Example -- Epidemiologic Information and Demand Reduction -- Implications of Epidemiologic Information for Effective Drug Abuse Prevention Strategies -- The Role of Treatment Data in Studying the Epidemiology of Substance Use and Abuse.