"A wide range of social indicators turned sharply negative for Blacks in the late 1980s and began to rebound roughly a decade later. We explore whether the rise and fall of crack cocaine can explain these patterns. Absent a direct measure of crack cocaine's prevalence, we construct an index based on a range of indirect proxies (cocaine arrests, cocaine-related emergency room visits, cocaine-induced drug deaths, crack mentions in newspapers, and DEA drug busts). The crack index we construct reproduces many of the spatial and temporal patterns described in ethnographic and popular accounts of the crack epidemic. We find that our measure of crack can explain much of the rise in Black youth homicides, as well as more moderate increases in a wide range of adverse birth outcomes for Blacks in the 1980s. Although our crack index remains high through the 1990s, the deleterious social impact of crack fades. One interpretation of this result is that changes over time in behavior, crack markets, and the crack using population mitigated the damaging impacts of crack. Our analysis suggests that the greatest social costs of crack have been associated with the prohibition-related violence, rather than drug use per se"--National Bureau of Economic Research web site.