One afternoon in 1967, Mo Ostin, an ascendant executive at what was then called Warner/Reprise Records, told his staff to quit doing what they had always been told was the most important part of their jobs. “We need to stop trying to make hit records,” he said. “Let’s just make good records and turn those into hits.”

Liberated from the strictures of AM radio, the company veered from the middle of the road into the hairy, scary wilderness of the hippie counterculture. By the end of the year, its artist roster included Jimi Hendrix, the Grateful Dead, Van Dyke Parks, Randy Newman, and the radical art band the Fugs. None of them sounded anything like the acts in the Top 40, but that was the point.