THE PURPOSE OF THIS STUDY WAS THE COLLECTION OF BASIC DATA ON RAPIDITY OF REHABILITATION OVER THE PERIOD FROM JANUARY 13 THROUGH MARCH 15, 1977, FROM AN INITIAL BODY OF 800 PROBATION CASES, MADE UP OF THOSE RELEASED ON PROBATION AND THOSE WHO HAD SERVED THEIR FULL TERMS. AGES OF SUBJECTS INVOLVED RANGED FROM 20 TO 70, WITH APPROXIMATELY 80 PERCENT OF THE SUBJECTS UNDER 40 YEARS OF AGE. THE MAJORITY OF THE SUBJECTS HAD BEEN CONVICTED FOR LARCENY OR CRIMES INVOLVING VIOLENCE, INCLUDING ASSAULT, RAPE, MURDER, INTIMIDATION, AND VIOLENT ROBBERY. SUBJECTS WERE ANALYZED IN TERMS OF SCHOOLING LEVEL, MONEY THEY HAD IN THEIR POSSESSION DURING INTERVIEWS DURING THE PAROLE PERIOD, STEADINESS OF OCCUPATION, CHANGE OF OCCUPATION, MARITAL STATUS, CHILDREN AND THEIR STATUS, PARENTS AND THEIR STATUS, AND PAST RECORD OF OFFENSES, AMONG OTHER FACTORS. GENERAL FINDINGS TENDED TO SHOW THAT MOST OF THOSE RELEASED ON PAROLE ACHIEVED MORE RAPID AND SUCCESSFUL REHABILITATION THAN THOSE WHO HAD SERVED OUT THEIR FULL TERMS. FULL COPIES OF THE VARIOUS SURVEY FORMS USED TO OBTAIN DATA ARE REPRODUCED AS APPENDED MATERIAL FOR REFERENCE, AND THERE ARE NUMEROUS CHARTS AND TABLES ARRANGING THE DATA IN VARIOUS WAYS FOR ANALYSIS. --IN JAPANESE.