Rick Strassman was permitted to embark on the first human research with psychedelic, hallucinogenic, or entheogenic substances in the 1990s in the United States after 20 years' intermission in the field. In the intermission period it has only been legally possible to research on animals.
Hallucinogenic substances have been instrumental in the foundation of many aspects of our cultural heritage. In this challenging program, McKenna suggests ways in which hallucinogenic plants have been associated with spiritual traditions in ancient India, in the Amazon and in medieval Europe.
