TERMS USED TO DESCRIBE DEGREES OF DRUG USE ARE REVIEWED. CATEGORIES OF DRUGS THAT ACCOUNT FOR MOST DRUG OFFENSES--DEPRESSANTS, STIMULANTS, HALLUCINOGENS, SOLVENTS/INHALANTS--ARE DISCUSSED, WITH REFERENCE TO ESTIMATES OF THE EXTENT OF THEIR USAGE. SPECIAL ATTENTION IS DIRECTED TO THE CONTROVERSY OVER DECRIMINALIZATION OF MARIHUANA POSSESSION AND USE. SOCIOLOGICAL, PSYCHOLOGICAL, AND OTHER THEORIES ABOUT THE CAUSES OF ADDICTION AND DEPENDENCE ARE REVIEWED, TOGETHER WITH VARIOUS TYPOLOGIES OF DRUG ABUSERS. PATTERNS OF OPIOID USE IN THE UNITED STATES, PARTICULARLY AMONG FEMALES AND OCCUPATIONAL GROUPS, ARE DISCUSSED. THE PATH OF HEROIN SALES IS TRACED FROM THE OPIUM FIELD TO THE USER. AN OVERVIEW OF LAW ENFORCEMENT INVOLVEMENT WITH DRUG OFFENDERS IS PRESENTED. SEVERAL DRUG TREATMENT APPROACHES ARE DISCUSSED, INCLUDING THE 'RATIONAL AUTHORITY' APPROACH (THE WILLINGNESS TO COERCE DRUG OFFENDERS INTO ACCEPTING TREATMENT), THERAPEUTIC COMMUNITIES, AND METHADONE MAINTENANCE. ESTIMATES OF THE SOCIAL COSTS OF DRUG DEPENDENCE ARE CITED, AND POLICY DEVELOPMENTS IN THE AREA OF DRUG ABUSE ARE SUMMARIZED. IT IS NOTED THAT THE GOVERNMENT STRATEGY FOR DEALING WITH DRUGS OF DEPENDENCE CONSISTS OF THREE PARALLEL ACTIVITIES: LIMITING SUPPLY, DISCOURAGING USE BY PREVENTION, AND TREATING USERS. IT IS POINTED OUT THAT SUPPLY REDUCTION, WHICH COSTS THE FEDERAL GOVERNMENT OVER $350 MILLION ANNUALLY, IS IMPRACTICAL IN A LARGE COUNTRY, THAT DEMAND REDUCTION THROUGH PREVENTION (WERE AN EFFECTIVE MECHANISM IS KNOWN) IS POLITICALLY UNATTRACTIVE, AND THAT TREATMENT IS EXPENSIVE AND POSES IDEOLOGICAL PROBLEMS. IT IS PREDICTED THAT POLICYMAKERS, WHO HAVE BEGUN TO UNDERSTAND THAT NOT ALL DRUG USE IS EQUALLY DESTRUCTIVE AND WHO ARE TRYING TO FOCUS ON THE DRUGS WITH THE HIGHEST SOCIAL COSTS (PRIMARILY HEROIN), EVENTUALLY WILL REALIZE THAT SUCCESS IN MINIMIZING DRUG ABUSE DEPENDS LESS ON SPECIFIC DRUG PROGRAMS THAN ON LARGER SOCIAL CHANGE (E.G., EXPANDING EDUCATION, TRAINING, AND JOB OPPORTUNITIES). A LIST OF REFERENCES IS INCLUDED. (LKM)