"Jails and prisons are designed to break human beings, to convert the population into specimens in a zoo - obedient to our keepers, but dangerous to each other. In response, imprisoned men and women will invent and continually invoke various and sundry defenses. Consequently, two layers of existence can be encountered within almost every jail or prison. The first layer consists of the routines and behavior prescribed by the governing penal hierarchy. The second layer is the prisoner culture itself: the rules and standards of behavior that come from and are defined by the captives in order to shield themselves from the open or covert terror designed to break their spirits."