The survey differs from previous statistical reviews of prison data in that it focuses on the number of months actually spent behind bars rather than on the terms of incarceration imposed by judges at sentencing. Among the major findings was that the average time served for felonies before parole in State prisons was 25 months, compared to 27 months in Federal prisons for Federal crimes. The average time served in individual jurisdictions ranged from a high of 53 months in Massachusetts -- mainly because of that State's stiff sentences for murderers -to a low of 13 months in South Dakota. No national standards for time served before parole exist for any class of felony, and the most severe jurisdictions require prisoners to serve at least twice as much time as the least severe jurisdictions for every category of felon. In the categories of rape and murder, prisoners in the most strict States served eight times as long on the average as did prisoners convicted of the same category of offenses in the most lenient States. In the category of negligent manslaughter, prisoners in the most strict State served more than 10 times as long as those in the most lenient. Women served significantly less time in prison before parole than men, and blacks served somewhat more time than whites or Hispanics. In general, southern States are more punitive than States in other areas, at least in time served before parole. Individual States varied widely in their overall use of parole, ranging from a low of about 24 percent of all Wyoming prisoners released in 1977 to more than 90 percent of prisoners released in Michigan, New Jersey, Ohio, and Utah. Survey limitations and numerous other results are described. Charts and data tables are included.