A cultural classic on the understanding of the marijuana experience, and reform of prohibitions against marijuana use by a professor of psychiatry at Harvard Medical School. Besides describing marijuana's psychological and physiological effects, the book includes a history of issues around the social acceptance, or lack thereof, of marijuana, and authentic descriptions of the nature of the "high" produced by marijuana. Pages 108-116 include a vivid essay describing the marijuana experience written anonymously by a friend of Grinspoon, Carl Sagan, published under the name of "Mr. X."

It should be noted that many of the observations reported in this book were made obsolete by the greatly increased potency of marijuana products that were developed decades after the book was published.