FIRST, A STUDY OF 5,794 BOYS AND 2,477 GIRLS AGES 15-17 IN VOCATIONAL SCHOOLS DURING 1967-68 LINKS SCHOOL PROBLEMS CLOSELY TO SOCIAL MALADJUSTMENT, ALTHOUGH LACK OF PSYCHOLOGICAL AND MEDICAL TESTS MAKE IT IMPOSSIBLE TO TOTALLY IDENTIFY THE FACTORS CHIEFLY RESPONSIBLE FOR THE SCHOOL PROBLEMS THAT SEEM TO INDICATE POTENTIAL DELINQUENCY. SECOND, RESEARCH ON 60 YOUNG ADULT MALES (AGES 17-20), 75 PERCENT OF WHOM WERE REPEAT OFFENDERS DETAILS CHARACTERISTICS SUCH AS EARLY CHILDHOOD BEHAVIOR, LACK OF SCHOOL ACHIEVEMENT, VOCATIONAL TRAINING (IF ANY), ALCOHOL CONSUMPTION, HOME ENVIRONMENT, RELATIONSHIP WITH PARENTS, AND THE DEGREE OF AGGRESSIVENESS. THIRD, AN ECOLOGICAL PROBE OF YOUNG WARSAW ADULTS WHO COMMITTED ACTS OF HOOLIGANISM, HALF OF WHOM WERE RECIDIVIST, EXAMINES THE CRIME RATE WITH PARTICULAR ATTENTION TO COMMERCIAL AND ENTERTAINMENT SECTIONS OF WARSAW AND COMPARISONS OF RESIDENCE AND OFFENSE. FOURTH, A STUDY OF RECIDIVISTS AND ALCOHOLICS WHOSE CRIME CAREERS HAD BEGUN LATE (AGES 25 TO 27) EXAMINES THE AMOUNT OF ALCOHOL CONSUMED, AND THE DIFFERENCES BETWEEN THESE OFFENDERS AND THOSE WHOSE FIRST CRIMES WERE COMMITTED AS JUVENILES. IN MOST CASES, AS SHOWN IN MEDICAL CERTIFICATES AND JUDICIAL AND PSYCHIATRIC EVIDENCE, MOST OF THEM WERE ALCOHOLIC WHEN THE FIRST CRIME WAS COMMITTED. AN EXPLANATION OF STATISTICAL MATERIAL IS APPENDED. (RFC)