IT IS CONCERNED WITH ACTS WHICH ARE RESPONSIBLE FOR THE MAJORITY OF JUVENILE COURT APPEARANCES: DISHONESTY, AGGRESSION, AND PROPERTY DESTRUCTION. MOST BEHAVIOR MODIFIERS HAVE TRIED TO CHANGE THE REINFORCEMENT CONTINGENCIES IN PROBLEM FAMILIES, SO THAT PARENTS NOTICE AND REWARD APPROPRIATE BEHAVIOR AND IGNORE THE INAPPROPRIATE. INDIVIDUAL CASES IN WHICH ARSON AND THEFT BEHAVIOR WERE MODIFIED ARE CITED. SIBLINGS AS WELL AS PARENTS CAN BE EFFECTIVE BEHAVIOR MODIFIERS. IN CASES WHERE PARENTS RESIST BEHAVIOR MODIFICATION TECHNIQUES, CHILDREN CAN BE TRAINED TO EXTINGUISH PARENTAL RESPONSES TO THEIR INAPPROPRIATE BEHAVIOR AND REINFORCE THEIR RESPONSES TO APPROPRIATE BEHAVIOR. EXPERIMENTS IN SCHOOLS HAVE SHOWN THAT WHILE CLIENT-CENTERED COUNSELING HAD LITTLE EFFECT ON DISRUPTIVE BEHAVIOR, BOTH SOCIAL REINFORCEMENT AND TOKENS, ESPECIALLY WHEN USED TOGETHER, WERE EFFECTIVE. PEER PRESSURES WERE FOUND USEFUL TO REDUCE STEALING IN CLASS BY REWARDING THE WHOLE GROUP IF NOTHING WAS STOLEN. CHILDREN CAN BE TRAINED TO ENFORCE THE POSITIVE BEHAVIOR OF THEIR TEACHERS. BEHAVIOR MODIFICATION IN THE COMMUNITY MIGHT CENTER AROUND A COMMUNITY OR YOUTH CLUB, AND UTILIZE THE BUDDY SYSTEM. STORES SHOULD REWARD SHOPPERS AND EMPLOYEES ENGAGING IN APPROPRIATE BEHAVIOR. ONE EXPERIMENT TRAINED DELINQUENTS TO INFLUENCE THE BEHAVIOR OF POLICE OFFICERS, WHO WERE THEN LESS LIKELY TO RATE THE YOUTHS AS SUSPICIOUS OR TROUBLEMAKERS. THE MOST SERIOUS METHODOLOGICAL PROBLEM WITH THESE EXPERIMENTS IS LACK OF FOLLOW-UP INFORMATION ABOUT THE PERCEIVED CHANGES. ETHICAL ISSUES CONCERNING BEHAVIOR MODIFICATION ARE BEST ALLAYED BY CONCENTRATING ON REWARD INSTEAD OF PUNISHMENT; BY USING EXPLICIT, NEGOTIABLE CONTRACTS; AND BY USING FULLY INFORMED, UNCOERCED SUBJECTS. REFERENCES ARE INCLUDED.