The study focuses on low-income, inner-city communities in which nonwhite minority residents are typically a majority of all residents. Illustrative materials are drawn primarily from research in New York City. Data show that the rapid expansion of illicit drug use in the inner cities in the 1960's has continued into the 1990's. Although the number of heroin users has remained relatively constatnt, the use and sale of cocaine has increased dramatically since the mid-1970's. Crack (freebase cocaine) became popular in many inner cities in 1986 and now dominates the illicit drug markets in many cities. The structure of drug-dealing organizations is complex and has job tasks that parallel those of many legitimate businesses. Cocaine and crack selling by inner-city youths have had major effects on low-income communities by offering economic opportunities that diminish the willingness of such youths to work at low-wage legal jobs. The violence that attends hard-drug use and selling also increased in the 1980's, and despite increased arrests of drug sellers, community safety in inner cities has declined substantially in recent years. Drug abuse has brought a decline in the economic well-being of most users and sellers, an increased risk of poor health and death at an early age, and a weakening of family relationships. 204 references (Author abstract modified)