The first generation of correctional facilities, the Pennsylvania and Auburn systems, were designed to formalize punishment in a secure and sanitary structure. This reflected the classical view of corrections which holds that criminal behavior is the free choice of the individual. The penalty for such behavior should fit the seriousness of the crime committed. By the late 1800's, there was increasing opposition to the classical view. The positivist view holds that crime is caused by a variety of biological or hereditary factors; the legal issue of free will is de-emphasized. Under this view, the rehabilitation of the individual offender is the primary goal of corrections. Although some of the positivist view was reflected in the first generation of prison design, as offenders were isolated in an attempt to change their behavior, the positivist view was reflected strongly in the second generation of prison design. These facilities, characterized by podular design and remote surveillance, have small, classified housing units to separate offenders by age, sex, crime, length of sentence, and aggressiveness. Because inmates are viewed as deterministically dangerous and irrational, staff persons are positioned behind barriers to avoid direct contact with inmates. The third-generation facilities, which emerged in the 1960's, involved the division of large prison facilities into smaller units directed by unit managers. Podular design and direct supervision evolved from the second-generation podular design with remote surveillance. These facilities reflect tenets of the classical school regarding free will, choice, and rational behavior. Positivist concepts are reflected in precise classification systems. Although there has been progress in prison designs in terms of the provision of humane conditions and the facilitation of rehabilitation, modern prisons share many of the problems of the prisons of the past, notably overcrowding, underfunding, and understaffing. 19 references.