Two trends in prison library history are the shift from a carefully circumscribed function to a more general collection of services and the move from a library orientation toward institutional goals to an orientation toward the needs and interests of inmate users. The public library has become the dominant model for prison library services due largely to benign neglect by correctional theorists and the professional librarians' predisposition toward the client-centered, service-oriented philosophy of the public library. This model for a prison library fails because it does not focus on the corrections mission in the public interest. The proposed 'change-based' model for the prison library calls for the library to be professionally supervised and organizationally independent of and on an equal status with other institutional programs. The library should be a voluntary-use program consistent with the traditional concept of libraries, in which materials and services focus on selected needs and interests of the users. Under the 'change-based' model, the library is developed as a resource in support of responsible and constructive inmate change. Appendixes contain American Correctional Association standards for prison libraries, a cooperative agreement between a university library and a department of corrections, and an Illinois joint statement on library service. 82-item bibliography and subject index.