An overview of State and Federal prison systems contains sections on the Federal Bureau of Prisons, State prisons and prison administration, and the total institution concept. A profile of prisoners in U.S. prisons focuses on sociodemographic characteristics of State and Federal prison inmates, the inmate population growth, and offense characteristics and sentence lengths. A description of types of prisons and their functions distinguishes prisons by their security classification. A review of inmate classification systems considers risk assessment and institutional placement, the functions of classification, types of risk prediction, and the accuracy and effectiveness of risk assessment devices. Following a listing of the distinctions between prisons and jails, the chapter then turns to a summary of prison functions, which include societal protection, punishment, rehabilitation, and reintegration. A discussion of prison culture focuses on inmate jargon and "pecking orders." The chapter concludes with brief discussions of the following selected prison issues: overcrowding; prison riots, inmate violence, and disciplinary measures; prison design and control; sexual exploitation; and inmates with communicable diseases. 7 tables, key terms, questions for review, and 5 suggested readings