A BATTERY OF FIVE PERSONALITY INVENTORIES WERE USED IN THIS STUDY: THE GUILFORD-MARTIN INVENTORY OF FACTORS, THE GUILFORD INVENTORY OF FACTORS, THE CALIFORNIA MENTAL HEALTH ANALYSIS, THE JOHNSON TEMPERAMENT ANALYSIS, AND THE MINNESOTA MULITPHASIC PERSONALITY INVENTORY. ALL 471 MALE INMATES WERE TESTED BEFORE RELEASE ON PAROLE, AND THEIR PAROLE RECORDS WERE THEN FOLLOWED FOR 1 YEAR. THOSE WHO WERE UNDER ACTIVE SUPERVISION OR HAD BEEN DISCHARGED WERE CALLED SUCCESSFUL PAROLEES. SUCCESSFUL PAROLEES WERE FURTHER DIVIDED INTO TWO GROUPS, THE 'BEST' PAROLEES AND THE 'DOUBTFUL.' SCORES ON THE PERSONALITY INVENTORIES WERE THEN CORRELATED AGAINST PAROLE PERFORMANCE. IT WAS FOUND THAT BOTH THE 'BEST' AND THE 'DOUBTFUL' GROUPS WERE MORE MASCULINE IN ATTITUDES AND INTERESTS THAN THE VIOLATORS AND WERE MORE SYMPATHETIC. THE 'BEST' GROUP WAS ALSO MORE CONFIDENT, LESS NERVOUS, AND MORE SATISFIED WITH WORK AND RECREATION. BOTH THE 'BEST' AND THE 'DOUBTFUL' GROUPS SHOWED LESS PHYCHOPATIC DEVIATION THAN THE VIOLATORS. IN ALL, 132 TEST ITEMS MET THE CRITERION OF SIGNIFICANCE AT A LEVEL OF .93 (7 PERCENT) OR HIGHER. VARIOUS TESTS OF SIGNIFICANCE ARE DETAILED. THE STUDY DATA IS PRESENTED IN BOTH NARRATIVE AND TABULAR FORM. EACH OF THE SIGNIFICANT ITEMS IS EXAMINED IN DETAIL. COPIES OF EACH OF THE FIVE TESTS ARE INCLUDED. THERE IS AN EXTENSIVE BIBLIOGRAPHY. THE STUDY CONCLUDES THAT THERE ARE DIFFERENCES IN THE THINKING OF PROSPECTIVE PAROLEES WHICH CAN BE ASSOCIATED WITH SUCCESS AND THAT THESE DIFFERENCES CAN BE MEASURED OBJECTIVELY. (AUTHOR ABSTRACT MODIFIED--GLR)