The subjects were recruited from the streets of northern Manhattan, from jail and prisons, from among arrested but released persons, from those on probation or parole, and from selected drug treatment programs. The study found that virtually all crack users had previously been monthly or more regular users of marijuana, cocaine, and often heroin prior to crack use. Crack sales became the most frequently committed crime and economically valuable drug for sellers. Violence was not linked to crack use but to frequency of selling cocaine and group selling. Women were apparently similar to their male counterparts when performing the same/similar roles in the cocaine economy. The crack era in New York had an incubation phase (1980-83), expansion phase (1984- 86), plateau phase (1987-89), and appears to be in a decline phase in the early 1990's. Marijuana, but not alcohol, appeared to be a central gateway to hard drug use. Punitive "get tough" policies were routinely imposed on crack sellers/abusers. Such responses swept crack sellers/abusers into the criminal justice system, but such resources were not well allocated to the most serious offenders. Criminal justice sanctions may temporarily interrupt careers, but recidivism was not related to severity of punishment. Recommendations derived from the study are to reduce reliance on punitive sanctions, provide drug treatment for crack and heroin abusers, and begin to address the major social inequalities in American society. An appended list of publications and presentations included in final report