THE PRINCIPAL ENVIRONMENT FOR THE PROGRAM WAS A SCHOOL SYSTEM AND ITS COMMUNITY IN A MIDDLE-CLASS SUBURB OF 120,000 PEOPLE. THE PURPOSE OF THE FOUR PROJECTS WAS TO UNDERSTAND AND MODIFY PARTS OF THE SYSTEM OF INFLUENCES THAT AFFECT ADOLESCENTS AS THEY MAKE DECISIONS ABOUT DRUG AND ALCOHOL ABUSE. AS A PREVENTIVE PROGRAM, TECHNIQUES OF SOCIAL (AS OPPOSED TO POLITICAL, LEGAL, OR ECONOMIC) INTERVENTION WERE AIMED AT REDUCING THE RISK THAT ADOLESCENTS WOULD MAKE DECISIONS ABOUT THE USE OF PSYCHOACTIVE SUBSTANCES WHICH WERE DELETERIOUS TO HEALTH, WELFARE, OR COMPETENT FUNCTIONING OF THEMSELVES OR OTHERS. BASIC ASSUMPTIONS OF THE PROJECTS WERE THAT THE HOME AND SCHOOL ARE THE MAJOR SOURCES OF INFLUENCES WHICH AFFECT THE DECISIONS ADOLESCENTS MAKE ABOUT DRUGS AND ALCOHOL. FOUR MAJOR PROJECTS OF THE PROGRAM ARE DESCRIBED: A STUDY OF THE ROLE OF COMMUNICATION, ATTITUDES, AND DISCIPLINE IN THE FAMILY AS IT PERTAINS TO DRUG AND ALCOHOL USE BY STUDENTS; A RESULTANT PARENT COMMUNICATION PROJECT WHICH GREW OUT OF THESE FINDINGS; A STUDY OF THE SCHOOL AS AN ORGANIZATION CAPABLE OF INCREASING OR REDUCING STUDENTS' READINESS TO USE DRUGS AND ALCOHOL; AND A TEACHER COMMUNICATION PROJECT GROWING OUT OF THE SCHOOL STUDY. APPENDIXES CONTAIN FACTOR ANALYSES AND TABULAR DATA. REFERENCES AND AN INDEX ARE INCLUDED. (MJW)