Crack's Decline: Some Surprises Across U.S. Cities examines the progress of the crack epidemic at each of 24 locations served by the Drug Use Forecasting program from as early as 1987 (for some locations) through 1996. In general, the study findings suggest drug epidemics tend to follow a natural course; drug epidemics tend to be local; local data can inform efforts to control drugs. Information about the prevalence of certain drugs, such as those monitored by the DUF program, can help identify the phase of a drug epidemic a community is experiencing, as it occurs. Changes in use by youths indicate important transitions in a drug's popularity.