Structured, self-administered questionnaires were given to adolescents of public secondary schools in New York State in the fall of 1971 and in the spring of 1972. Usable questionnaires were obtained from 8,206 and then from 7,250 students—an 81% response and a 76% response respectively. Four stages of drug use were identified: 1, beer or wine; 2, hard liquor or tobacco; 3, cannabis; and 4, other illicit drugs. Beer and wine are the first substances used, then tobacco and alcohol. The use of marijuana rarely takes place without prior use of liquor, tobacco, or both. Similarly, the authors find that the use of other illicit drugs (hashish, psychedelics, cocaine, heroin, etc.) rarely takes place before experimentation with marijuana.