The analysis of why inmate populations continue to increase concludes that it is not due to an increase in crime but rather to changes in sentencing policy that have increased the proportion of felony convictions that result in prison sentences and also in the length of prison sentences. In addition, the rate of reimprisonment for offenders has increased due to increased surveillance over those released from prison and a failure to assist in their reentry into society through support systems that facilitate their transition from prison to the community. The report's recommendations are designed to reduce the number of people sent to prison, along with the length of time spent in prison for those who are imprisoned and the period spent on probation and parole, which increases the risk for technical violations penalized by imprisonment. The recommendations essentially re-establish practices that were the norm in America for most of the 20th century, when incarceration rates were a fraction of the current rate. Recommendations for changing current sentencing laws and correctional policies have been analyzed for their practicality, cost-effectiveness, and risk for jeopardizing public safety. The recommendations would reduce time served in prison; eliminate imprisonment for parole or probation technical violators; reduce the length of parole and probation supervision periods; and decriminalize "victimless" crimes, particularly those related to drug use and abuse. If implemented nationwide, the recommendations would gradually and safely reduce the Nation's prison and jail populations to half their current size. This reduction would generate savings of an estimated $20 billion a year that could then be available for funding more promising crime-prevention strategies. 12 tables and 5 figures