PHASE ONE OF THE STUDY IN NASSAU COUNTY, N.Y., COVERED THE EARLY EPIDEMIC YEARS OF DRUG ABUSE, 1967-1971, AND CONSISTED OF AN ANALYSIS OF DATA ON SOME 9,587 DRUG OFFENDERS. STUDY OBJECTIVES FOCUSED ON THE EPIDEMIOLOGY OF DRUG ABUSE IN THE COUNTY, THE DEVELOPMENT OF A CLASSIFICATION SYSTEM THAT WOULD ENCOMPASS THE MAJORITY OF THE TYPES OF DRUG ABUSERS, AND A SERIES OF DRUG OFFENDER PROFILES. ANALYSES OF THE SCOPE, ETIOLOGY, INCIDENCE, AND PREVALENCE OF THE VARIOUS TYPES OF DRUG ABUSERS, AS WELL AS THEIR DEMOGRAPHIC, SOCIAL, LEGAL, ECONOMIC, RACIAL, CULTURAL, AND FAMILY BACKGROUND CHARACTERISTICS WERE CONDUCTED. PHASE TWO OF THE STUDY EXAMINED DRUG ABUSE DURING THE PERIOD 1972-1975, EXAMINING 12,058 DRUG ABUSERS. IN ADDITION, THE YEARS OF 1976 AND 1977 WERE USED FOR FOLLOWUP AND PROGRAM OUTCOME EVALUATIONS, AS WELL AS FOR COMPARATIVE ANALYSES OF THE FINDINGS DERIVED FROM THE FIRST TWO PHASES OF THE STUDY. PHASE TWO ALSO INCLUDED EFFORTS TO ASSESS THE EFFECTIVENESS OF THE COUNTY CRIMINAL JUSTICE SYSTEM IN THE MANAGEMENT OF DRUG ABUSE OFFENDERS, THE RELATIONSHIP BETWEEN DRUG ABUSE AND OTHER TYPES OF CRIME, AND THE IMPACT OF SOCIAL POLICIES AND PROGRAMS ON DRUG ABUSE. EVIDENCE FROM THE STUDY INDICATES THAT THE NASSAU COUNTY CRIMINAL JUSTICE SYSTEM HAS BEEN SUCCESSFUL IN ITS MANAGEMENT OF ILLICIT DRUG ABUSE AND THAT ITS EFFECTIVENESS INCREASED OVER THE YEARS MONITORED BY THE STUDY. THIS GROWING EFFECTIVENESS IN COMBATING THE PROBLEM IS BELIEVED DUE TO THE EFFORTS OF THE CRIMINAL JUSTICE SYSTEM TO PROVIDE THE QUANTITY AND QUALITY OF PROGRAMS AND SERVICES DICTATED BY THE SCOPE AND NATURE OF DRUG ABUSE AND RELATED CRIME. WHILE THE STUDY FOUND NO RELATIONSHIP BETWEEN MARIHUANA ABUSE PER SE AND OTHER KINDS OF CRIMINAL BEHAVIOR, IT WAS FOUND TO BE THE DOMINANT DRUG OF ABUSE, INCREASINGLY SO OVER THE PERIOD OF THE STUDY. HEROIN ABUSE RANKED HIGHEST WITH PERSONS OF LOW MEDIAN FAMILY INCOME. CRIME WAS FOUND TO BE HIGH IN NEIGHBORHOODS OF LOW INCOME LEVEL. WHILE USERS OF DRUGS WERE INCREASINGLY DIVERTED FROM THE CRIMINAL JUSTICE SYSTEM INTO REHABILITATION PROGRAMS, SELLERS OF DRUGS WERE DEALT WITH THROUGH PROBATION AND INCARCERATION, WITH HEROIN TRAFFICKERS MOST OFTEN INCARCERATED. DATA FROM THE STUDY ARE PROVIDED, ALONG WITH SELECTED REFERENCES. (RCB)