The first section contains studies on typologies of lifestyles and drug using careers. The next section focuses on the natural history of addiction and includes research on occasional users, initiation into drug use, abstinence and relapse phenomena, maturing out, and follow-up studies. The literature on characteristics of heroin addicts is included, emphasizing psychosocial patterns and characteristics unique to females and ethnic groups. The final two sections cover drug use patterns and theories of addiction. Each research project synopsis consists of a summary, methodology, findings, and conclusions.