Prison reform has been a recurrent phenomenon in the United States throughout the almost 200 years such institutions have existed. The type of reform has varied according to the change agent or what was viewed as the primary problem requiring attention. Generally prison reform has been inseparable from the promotion of change in the prison's environment. A broad change over the last 100 years has been reduction in the prison's isolation from the community and in the autonomy of the warden. Inmates have greater access to the community, its services, and the rights guaranteed other citizens, and the warden's control of prisoners is constrained by newly defined rights of prisoners and freer communication. This century has seen movements towards reduced use of prison, amelioration of the prison experience, and emphasis on rehabilitation, but these movements are now being counteracted by opposition to indeterminate sentencing, the use of prison to provide a fixed and just punishment for crimes committed, voluntary participation in rehabilitation programs, and the provision of a humane environment and the securing of prisoners' rights. There is general agreement that the upgrading of the prison system must include the provision of humane facilities and environments. If the use of imprisonment as a response to crime continues at its present level or increases, then additional expenditures must be provided to establish such facilities and environments. An alternative is to develop less costly means of providing humane and effective corrections programs. Ten footnotes are listed.