Legislators, journalists and concerned citizens in general, when consider ing what to do about the plague of heroin addiction in large cities, ask an obvious question: "Is methadone treatment effective?" This question is a critical one since maintenance with methadone is at present the only prac tical alternative to leaving tens of thousands (in New York City, hundreds of thousands) of untreated addicts on the streets. Other treatments, although effective for limited groups, could not conceivably be expanded to stop heroin use in as much as 10% of the addicted population. The present study,...