The theme of this booklet is that part of the long-term solution to the overcrowding crisis will involve building new prisons and jails, but, in many cases, this costly and problematic step can be avoided. Planning a prison or jail that will be useful for several decades requires both forward-thinking architectural design and a clear sense of what society's needs will be in the next century. In developing this theme, the true costs of prison construction are identified, including hidden construction costs, cost overruns, financing costs, hidden operating costs, and long-term costs. Also considered are the monies lost to other public services because of prison construction. These costs are weighed against the questionable benefits of prison, notably incapacitation, deterrence, and rehabilitation. In examining the management of the corrections and court systems to reduce prison and jail populations, attention is given to planning structures, inmate population projections, setting limits on inmate populations, sentencing guidelines, community corrections, and regional corrections systems. A review of strategies for reducing jail populations categorizes them according to reductions in bookings and ways to secure earlier releases. Strategies for reducing prison populations are reviewed as well. Given the decision to proceed with prison or jail construction, advice is provided on how to plan a facility that will meet future needs. A resource guide lists organizations and publications.