Attention was focused on individuals who were currently or recently addicted, and the sample included more black than white addicts. The interview/questionnaire provided information in several areas of interest: addict's life up to the time of addiction onset, demographic characteristics, events and conditions of early life history such as deviant behavior and drug abuse prior to addiction onset, addict treatment history, and addict's life during the period of addiction. It was found that treatment was generally sought because addicts felt pressured to do so. Those who sought treatment due to pressure from authorities were less likely than others to be in methadone maintenance, but methadone maintenance was still the most popular treatment. Most addicts who entered treatment continued to use drugs to some extent during treatment. Considering the nature of motivation for treatment and the very low commitment on the part of many addicts, it was not surprising that most addicts tended to evaluate the quality of treatment as inadequate and to report a low level of satisfaction with it. Perhaps the most distinguishing characteristic of drug addicts was a tendency toward criminality, specifically violent crimes and crimes against property. In addition, addicts were characterized by risk taking behavior and impulsivity. The typology of addicts is based on treatment experiences, criminality, social activities, and psychopathology. 8 references and 24 tables