Based on a literature review, the study identified a significant research gap: a better understanding of criminal events, particularly the role of drugs and alcohol in such events, was needed. The analytic focus of this research was primarily on successful serious crimes (robbery, burglary, and larceny) and on whether various drugs and/or alcohol were used before, during, and shortly after such crimes. The analyses were designed to show whether and how specific substances influenced specific types of crime events. To study serious crime events, research staff recruited 105 male drug abusers from East Harlem (New York City) who were also highly active criminals. Subjects were primarily black and Puerto Rican males who had grown up in the low-income neighborhoods from which they were recruited. The interview schedule obtained extensive data on the subjects' backgrounds, criminality, and drug use patterns in their lifetime, past 12 months, past month, and past 24 hours. The associations between robberies and cocaine and/or heroin use were primarily due to the complex behaviors of high-rate robbers. They were more likely to be daily and multi-daily users of cocaine, heroin, and other drugs than low-rate robbers. Although a large proportion of the subjects used specific substances before, during, and after the focal crimes, there were few or no significant associations. Suggestions for future research are offered. Chapter tables, 63 references.