This paper identifies likely important research directions in drug and alcohol studies during the next quarter century. The discussion focuses first on several emergent trends in contemporary research which have the potential to make crucial contributions both to our general understanding of psychoactive substance use and associated disorders, and to the promotion of international public health. Implications of these developments for future research agendas are discussed, including the study of drugs, alcohol, and AIDS; prevention strategies; problem rates; and the study of traditional and modern uses of psychoactive substances.