For many, the psychedelic Sixties began at an event called the Trips Festival that took place in San Francisco the third weekend of January 1966.

At the three-day blowout, between 3,000 and 5,000 people tripping on LSD — more than had ever experienced the drug together — let loose.

Grateful Dead guitarist Jerry Garcia called it “total, wall-to-wall gonzo lunacy,” noting there were “people jumping off balconies onto blankets and then bouncing up and down.” Hells Angels fought with other biker gangs while a member of the Merry Pranksters, the experimental LSD crew of author Ken Kesey — who attended the event in a “silver space suit with a helmet” — tried to pull Janis Joplin and her band off stage after just one song.

And at the center of it all was the man who made it happen — Owsley, the psychedelic pioneer who provided the LSD.

This new biography positions Owsley, as both he and his brand of LSD came to be known, as wizard, madman and genius. In addition to creating the most pure and powerful LSD on the planet, he began the tradition of taping the Dead’s shows and developed what was, at the time, the world’s greatest live sound system.

For all his contributions to music, though, it was Owsley’s acid that made him a household name; the Oxford English Dictionary added “Owsley” as a word in 2005.

Augustus Owsley Stanley III (later nicknamed Bear) was born on Jan. 19, 1935. His grandfather, Augustus Owsley Stanley, had been a US senator and the governor of Kentucky.

The anti-authoritarian autodidact began smoking marijuana and taking LSD and speed in 1964 and became a drug advocate. But when he couldn’t find any LSD, which was then still legal, the college dropout learned to make it himself.

Walking into a chemistry lab at UC-Berkeley, hoping to find a scale to weigh his speed, he met a chemist named Melissa Cargill, and spoke to her about the chemistry of psychedelics. Owsley invited her to coffee, and within three days, Cargill broke up with her fiancé, abandoned thoughts of grad school and moved in with Owsley.

He spent several weeks studying chemistry at the university library, and, with Cargill’s help, began making his own LSD. By March 1965, the two had succeeded in creating the purest LSD to date. They began producing it in bulk, and word spread.

Owsley and Cargill set up shop in an LA apartment and produced around 800,000 hits of LSD, which was made illegal in October 1966. He intended to stay under the radar, but when a local musician he sold to began telling people who made the drug, his name stuck.

“I had nothing to do with that, and I did everything I could to stay out of it,” Owsley said. “I wasn’t trying to create a f—ing myth — I was just trying to stay out of jail.”

Over the next year, Owsley became friends with the Dead, taking over as their sound man and providing them with LSD.

His acid, meanwhile, became a cultural touchstone. Musicians including the Dead, the Jefferson Airplane and Frank Zappa wrote songs either mentioning or inspired by him.

At the Monterey Pop Festival in June 1967, The Who’s Pete Townshend took a hit. “Owsley was introducing, like, Version 7 of his own acid,” Townshend said, noting that “you had no clue” what you were getting. “I took some of his at Monterey and I never touched a drug again for 18 years. It was extraordinarily powerful.”

John Lennon, who had developed an appreciation for LSD in England, “had become fixated on how he could continue to obtain enough high-quality acid to fuel his creative endeavors.”

He approached Owsley about a lifetime supply but was uncertain how to get it into England.

When he couldn’t find any LSD, which was then still legal, the college dropout learned to make it himself.

“Lennon sent a cameraman there to shoot the festival,” writes Greenfield. “The cameraman’s real job was to smuggle the acid back through English customs [in his telephoto lens].”

The effects of the Beatles’ trips on Owsley acid likely fueled the band’s trippy “Magical Mystery Tour” film, which was shot shortly after.

Not every musician was on board. When Owsley offered a tab to Ravi Shankar at Monterey, “the famed Indian sitar player promptly turn[ed] away from him and stalk[ed] out of the room.” And when Owsley met Bob Dylan in New York, he introduced himself by saying, “Hi Bob. I’m Owsley. Want some acid?” Dylan replied, “Who is this freak? Get him out of here!”

After a friend sold $3,400 worth of Owsley acid to an undercover agent in December 1967, Owsley’s home was searched and authorities found 67.5 grams of LSD, enough to make around 700,000 doses.

He was arrested and convicted, and served two years in prison. After his release, he had changed, becoming, according to a friend, “dark and dour.”

Owsley worked with the Grateful Dead on and off for decades and moved to Australia in his later years. He died from injuries suffered in a car crash on March 12, 2011.

Dead lyricist John Perry Barlow once met Albert Hoffman, creator of LSD, at a conference, and the discussion tuned to Owsley.

“[Hoffman] was quite impressed with what Owsley had done, as he was the only one who had ever got [the chemistry] correct,” writes Greenfield, citing Barlow.

“On every level, it was the ultimate confirmation that Owsley had come up with the real thing.”