The five primary areas related to prison crowding research are discussed. These include the eighth amendment test of cruel and unusual punishment, ecological versus individual level differences in crowding, theoretical and empirical problems associated with violence and its relation to crowding, an analysis of inmate illness reporting and its relation to crowding, and the degree to which the literature points to consistency both within the prison and across other crowded settings. It is concluded that: (1) the first criterion cannot be met based on the extant crowding literature; (2) there is no clear relationship between crowding and violence; (3) the most demonstrative finding of dormitories being associated with higher illness reporting rates is an artifact of selection bias; and (4) illness reporting is affected as much by psychological and sociological causes as by the health status of the inmate. There is little consistent evidence supporting the contention that short- or long-term impairment of inmates is attributable to prison density. 2 figures, 2 notes, and 81 references (Author abstract modified)