clinics using "psycholytic therapy"—a form of psychotherapy involving the controlled use of psychedelic drugs. Sandoz marketed and sold pure psilocybin under the name Indocybin to physicians and clinicians worldwide. There were no reports of serious complications when psilocybin was used in this way. In the early 1960s, Harvard University became a testing ground for psilocybin, through the efforts of Timothy Leary and his associates Ralph Metzner and Richard Alpert (who later changed his name to Ram Dass). Leary obtained synthesized psilocybin from Hofmann through Sandoz pharmaceutical. Some studies, such as the Concord Prison Experiment, suggested promising results using psilocybin in clinical psychiatry. According to a 2008 review of safety guidelines in human hallucinogenic research, however, Leary and Alpert's well-publicized termination from Harvard and later advocacy of hallucinogen use "further undermined an objective scientific approach to studying these compounds". In response to concerns about the increase in unauthorized use of psychedelic drugs by the general public, psilocybin and other hallucinogenic drugs suffered negative press and faced increasingly restrictive laws. In the United States, laws were passed in 1966 that prohibited the production, trade, or ingestion of hallucinogenic drugs; Sandoz stopped producing LSD and psilocybin the same year. Further backlash against LSD usage swept psilocybin along with it into the Schedule I category of illicit drugs in 1970. Subsequent restrictions on the use of these drugs in human research made funding for such projects difficult to obtain, and scientists who worked with psychedelic drugs faced being "professionally marginalized". Despite the legal restrictions on psilocybin use, the 1970s witnessed the emergence of psilocybin as the "entheogen of choice". This was due in large part to a wide dissemination of information on the topic, which included works such as those by author Carlos Castaneda, and several books that taught the technique of growing psilocybin mushrooms. One of the most popular of this latter group was published in 1976 under the pseudonyms O.T. Oss and O.N. Oeric by Jeremy Bigwood, Dennis J. McKenna, K. Harrison McKenna, and Terence McKenna, entitled Psilocybin: Magic Mushroom Grower's Guide. Over 100,000 copies were sold by 1981. As ethnobiologist Jonathan Ott explains, "These authors adapted San Antonio's technique (for producing edible mushrooms by casing mycelial cultures on a rye grain substrate; San Antonio 1971) to the production of Psilocybe [Stropharia] cubensis. The new technique involved the use of ordinary kitchen implements, and for the first time the layperson was able