Thursday, August 8, 1968 closed the Chambers Brothers at the Fillmore West, ending the front half of Lee Conklin's BG-132 before Eric Burdon took the same poster.

The Chambers Brothers were four brothers from Mississippi plus a drummer from Brooklyn, playing gospel-rooted soul that had absorbed rock and psychedelia, and "Time Has Come Today" — eleven minutes of cowbell, feedback and shouting in its album form — was on the radio that summer. They were among the very few Black rock bands with a large white ballroom following, and they played Graham's rooms constantly.

The Charlatans beneath them were by 1968 the scene's overlooked founders: the Red Dog Saloon band from the summer of 1965, whose Michael Ferguson and George Hunter handbill predates BG-1 by most of a year and is routinely called the first psychedelic rock poster. Three years on they were second-billed and still without a recording career worth the name.

A numbering trap worth restating: BG-132 (Bill Graham, Fillmore West) and FD-132 (Family Dog, Avalon) ran the same week — two series, one number, the same week, different posters. They are routinely conflated and must never be merged.