Prison populations are determined by policy choices, and there are three general policy options; expansion, which is committed to the belief that an expanded prison system will benefit society; standstill, which aims at holding prison populations steady; and reduction, which aims at reducing the use of prison. The pattern of prison system growth in England since World War II has been steadily expansionist, although efforts were made after the mid-1970's to effect a standstill policy. The consequence of expansionist and standstill policies is that prison systems house both serious and trivial offenders. Standstill policy is unlikely to be an effective counter to expansionist pressures, as the custodial threshold is lowered to include persons who earlier would have been fined or dealt with by noncustodial means. Expansionist policy is costly, ineffective in dealing with crime, and demeaning to the society that embraces it. Reductionist strategies, such as those of Japan and Holland, aim at limiting imprisonment to serious offenders. A reductionist strategy promises to be effective only if prison populations are first limited, followed by the development of an array of noncustodial options for less serious offenders. Items on the reductionist agenda include (1) a substantial reduction in the physical capacity of the prison system, (2) legal enforcement of the minimum standards for the physical conditions of imprisonment, (3) enforcement of an optimal staff-to-prisoner ratio, (4) the use of early-release mechanisms to avoid prison overcrowding, (5) the structuring of sentencing discretion toward the use of the least restrictive sanction, and (6) an exceptional use of imprisonment for the breach of noncustodial sanctions. A bibliography of 211 entries is provided along with a subject index.