The analysis uses the inductive method to study the Texas Department of Corrections, using information from staff reports, inmates, inmate records, files on prison gangs, personal observations, and interviews with prison gang members who defected. According to the model, the development of prison gangs involves a 5-stage process. In Stage One, a convicted offender is sentenced to serve time in prison, thereby being separated from the traditional support system and needing to deal with prison guards and other inmates. In Stage Two, the inmate overcomes feelings of isolation, fear, and danger by socializing with certain inmates and becoming part of a clique. While some cliques disband in time due to unit transfer or release of members, others evolve into Stage Three, self-protection groups. As members of a self-protection group gain increased recognition from other inmates, certain members exert stronger influence over other members and contemplate leading the group into Stage Four, a predator group. As members of the predator group enjoy their increased protection and their new-found power over other inmates, they may evolve into Stage Five, a prison gang, which requires involvement in contract murder, drug trafficking, extortion, gambling, and homosexual prostitution. Gang members must wear tattoos, make a lifetime commitment, and function as part of a formal and paramilitary organizational structure. As of December 1990, the Texas Department of Corrections had identified and confirmed 8 prison gangs with a total membership of 1,174. Charts, figures, and 30 references