On January 14, 1967, more than 20,000 people gathered in Golden Gate Park for the Human Be-In, a daylong happening that set the stage for the Summer of Love. Billed as “A Gathering of the Tribes,” it aimed to unite two strands of the 1960s counterculture: the Berkeley New Left, rooted in antiwar and civil rights activism, and the Haight-Ashbury scene, rooted in psychedelics, music, and communal living. Allen Ginsberg stood at the center. As the Grateful Dead launched into “Dancing in the Street,