This review examines trends in marijuana use through a study employed to track the progress of the recent epidemic among arrestees at 23 locations across the nation. It identifies nationwide drug use trends within the mainstream population on the basis of self-reports of past-month use, a measure parallel to the length of time in which marijuana can be detected by urinalysis. It compares the recent marijuana upsurge with that observed for previous crack and heroin epidemics, and indicates that modest increases in youthful marijuana use within the mainstream population started in 1992 and plateaued in 1996. It suggests that the gateway theory may be less relevant in these youth since they have been much less prone to advance to other drugs than their predecessors following experimentation with marijuana. Ethnographic studies in inner-city communities suggest that there has been a shift in the subculture of drug use and that interpersonal interactions have become more congenial and less violent. Prevention aimed at providing youth in distressed inner-city households with a greater stake in society may ensure further declines in drug abuse and its attendant criminality. Twenty-eight figures are used to explain marijuana use throughout the nation. (JDM)