The contrast of these neighborhoods permitted an analysis of the effects of neighborhood change and structure on participation in drug selling and its consequences for residents who were active in the local drug industry. Critical questions in the research involved whether the growth of drug markets in an area of declining licit economic activity led to the siphoning of well-educated and employed people into the informal and illicit drug economy and spurred entry into other criminal activities. The study sample was constructed to represent patterns of crack, cocaine, heroin, and polydrug (primarily marijuana) drug use and selling; it included arrestees who were awaiting initial court appearances. Interviews revealed that violence in drug selling was associated with the extent of the selling group's formal organization. The association between drug selling and nondrug crime suggested that participation in systemic violence was part of a pattern of generalized crime. Group drug sellers were more active criminally than independent drug sellers and nonsellers, and male drug sellers were more active than female drug sellers. Earnings from drug selling exceeded earnings from legitimate work by a wide margin. Legal labor market participation competed with the alternatives of drug selling and criminal activity. There was a paradoxical relationship between the social and economic health of study neighborhoods and the social organization and economics of drug selling. The local drug economy seemed to be a function of political decisions and economic forces that extended well beyond the borders of a single neighborhood. Supplemental study data are appended. 71 references, 21 footnotes, and 14 tables