From November 3, 1970, to November 2, 1972, all 1,345 incoming prisoners became members of the research cohort. Of these, 64 percent were white, 35 percent were black, and 1 percent were American Indians. Their mean age was 22.5; their mean Beta Intelligence Quotient was 101; and their highest grade level attained averaged 9.9. The vast majority had been convicted for crimes against property. For the first study, a structured prerelease interview was administered within a few days of each inmate's departure. About 84 percent of the inmates surveyed felt that prison had changed them for the better, 9 percent felt they had not changed, and 7 percent thought they had changed for the worse. Personal changes pertained to 'time to think' (22 percent), 'just being here' (12 percent), changes made in themselves (10 percent), and the influence of other inmates (9 percent). Also, 78 percent felt than prison did not rehabilitate offenders. The second study compared personality test scores (the Minnesota Multiphasic Personality Inventory and the California Psychological Inventory) of inmates upon entry with those received upon release. For both blacks and whites, the results indicated general improvement. Significantly more ego strength and maturity, less depression and anxiety, and reduced inclinations towards antisocial and criminal behavior were measured upon release. The third study examined recidivism. Of 1,008 subjects whose records were available, 71.4 percent had no new convictions within a mean period of 43 months (using a standard deviation of 11 months). These studies refute the popular myth of the disturbed, bitter, and recidivist ex-offender. Graphs and tables, footnotes, reference notes, and 10 references are included.