Although African Americans made up 41.3 percent of the nongang group, they accounted for only 7.4 percent of gang members. Similarly, white inmates were represented proportionately higher in the nongang group (38 percent) than among gang members (20.2 percent). Hispanic inmates comprised the majority of gang members. Gang members were slightly younger when they entered prison than nongang members, and gang members had more convictions than nongang members. The most frequent offense for both groups was burglary. Gang members were more likely to have a violent current offense than nongang members, and gang membership was influenced by the amount of prior time served in prison. Although gang members constituted a small percentage of the inmate population, they contributed disproportionately to prison violence and vice. Most prison killings and a large proportion of assaults and other violent offenses were gang- related. Inmate gangs were responsible for many illegal activities in prison, and they often controlled drug trafficking, prostitution, contract killings, and protection rackets. Prison staff perceptions of gang objectives varied dramatically. Some prison officials believed one of the primary goals of gangs was to undermine prison officials. 10 tables