America is a big place with a deep, wide, and--as depicted in Jesse Jarnow’s Heads--high socio-cultural history.

The book begins with a map, first published in 1968, a synergistic creation of two heads, one of whom “holds the distinction of procuring the first acid ever taken by Jerry Garcia.” Humbead’s Map of the World displays a large landmass consisting of San Francisco, Berkeley, Cambridge, and New York City in almost equally dominant proportions, a smaller blot for Los Angeles and a tiny spot in the middle labeled N. Africa. For the drug culture of the 1960s, that was the universe, and acid was the final frontier.

Lysergic Acid Diethaylamide was compounded by Albert Hofmann, in Switzerland, in 1938. Developed for its possible medicinal uses, not habit-forming, not especially harmful if taken in optimal circumstances, a “hit” of the drug about the size of a grain of sand could tear your mind apart and reconstruct it in the space of about ten hours. And, for a short blissful period, LSD was perfectly legal, if hard to procure.

Then a science-minded subculture waif named Owsley Stanley found a way to manufacture this incredible boon to mankind in his home, and in the main, gave it away to thousands of hippies, many of whom were gravitating like iron filings to a giant magnet toward the music of the Grateful Dead. “Our audience is almost always heads,” Jerry Garcia correctly pronounced; drugs would follow the Dead for another twenty years. Psychologist Timothy Leary made “dropping” LSD a sacrament, poet Allen Ginsberg made it a writer’s badge of honor, and a slew of graphics prodigies were inspired by it to create ultra mind-blown images, an attempt to replicate the stoned panorama. To those doing it, it seemed like everyone was doing it. But by 1971, international law took its course, ruling that something so enjoyable had to be bad for you, and LSD became a Schedule 1 substance. The times they were indeed a-changin’.

In this lengthy, well-researched, rollicking romp, author, radio host, and alternative journalist Jarnow concentrates much of his acid bio on the sustained success of musically gifted Garcia and The Dead—their wild concerts, stream-of-consciousness proclamations, strident exhortations to get high, stay high—as the hard core of psychedelia. Jarnow reveals that in the minds of some, the psychedelic movement has not waned, though the use of LSD and its many chemical successors has, undeniably. Some in the movement like to think that cyberspace became the new high, despite Jarnow’s account of Steve Job’s refusal to take a hit of acid when it was offered, saying, “Oh, I cant take this, it’s probably poison.” In his nineties, Albert Hofmann expressed his mild regret that his chemical miracle might have kept people from going to church.

The one missing square in Jarnow’s giant Rubik’s cube is, arguably, the opposition within the subculture to the use of acid, the philosophies of those who turned on, tuned in, dropped out, and then for various but often clearly articulated reasons, rejected the drug ethos. Among those were Timothy Leary’s former colleague Richard Alpert, who became the self-styled guru Baba Ram Dass, and the followers of Indian spiritual master Meher Baba. But probably many, if not most, former heads just wanted to get a haircut, get a job, and leave the toys of childhood behind.

Jarnow is convinced that “the entheogenic revolution” still flourishes today, especially in its old haunts, those depicted on Humbead’s map, and concludes that the drugs are still around for those with the will to find them.