Information on the Federal prison system was obtained primarily through discussions with Bureau of Prisons officials and the United States Sentencing Commission, reviews of Bureau documentation, and visits to five Federal prisons. Data on State and military prisons were obtained from the Bureau of Justice Statistics, the Defense Department, and visits to two military prisons. The study concludes that the Federal Bureau of Prisons faces unprecedented crowding and an increasing inmate population. Its plan, as presented in the fiscal year 1990 budget submission, calls for spending $1.8 billion to double prison capacity by 1995. Recent estimates by the Bureau indicate an even larger prison population by 1995 than anticipated when the plan was developed. Congress, the administration, and the judicial branch must address a number of issues over the next few years. Decisions will be needed on issues such as the types and sizes of needed prisons, the potential for "privatizing" prisons, and the feasibility of alternatives to traditional incarceration. Some possibilities are military-style prisons oriented toward discipline and electronically monitored home detention. State officials must make similar decisions, as they too face problems of prison crowding and escalating prison populations. Appended tables and figures.