THIS CALIFORNIA BASED PROJECT WAS UNDERTAKEN TO ORGANIZE THE RESULTS OF AN EXTENSIVE DATA COLLECTION ON THE YOUTHFUL OFFENDER AND TO PROVIDE A RESOURCE FOR THE CORRECTIONAL THEORIST WORKING WITH THIS MOST IMPORTANT OFFENDER GROUP. BACKGROUND DATA, PERSONALITY AND OTHER TEST RESULTS, ACADEMIC AND VOCATIONAL SKILLS AND ATTITUDES, AND PSYCHIATRIC FACTORS, AS WELL AS OFFENSE RELATED INFORMATION AND THE RATINGS AND RECOMMENDATIONS OF INSTITUTIONAL STAFFS WERE OBTAINED ON 4,146 MALE CALIFORNIA YOUTH AUTHORITY PAROLEES. THIS EFFORT WAS ENVISIONED AS A PREREQUISITE TO THE DEVELOPMENT OF TYPOLOGICAL DESCRIPTIONS OF YOUTHFUL OFFENDERS THAT MAY ULTIMATELY INFLUENCE THEIR TREATMENT AND REHABILITATION. AFTER PROVIDING A BRIEF BACKGROUND ON THE ENTIRE STUDY AND A REVIEW OF THE LITERATURE ON JUVENILE DRUG USE IN RELATION TO DELINQUENCY, THIS VOLUME PRESENTS COMPARATIVE DATA ON SIX SUBGROUPS, CLASSIFIED BY THE SEVERITY OF USE OF DRUGS, ALCOHOL, OR OPIATES. USING ALCOHOL AND DRUG USE AS CONTROLLED VARIABLES, DATA IS THEN PRESENTED ON CASE HISTORY, INTELLIGENCE, ACADEMIC, VOCATIONAL, PERSONALITY, PSYCHIATRIC, AND OFFENSE-RELATED FACTORS FOR THE JUVENILES STUDIED. THE RELATIONSHIP OF THESE VARIABLES TO PAROLE SUCCESS IS ALSO ANALYZED. FOR OTHER DOCUMENTS ON THIS PROJECT, SEE NCJ-19482-19485, 38967, AND NCJ-38969-38972....DMC