The BG-25 poster is one of the great might-have-beens of the Fillmore. On Friday, August 26, 1966 (a two-night run, Aug 26-27), Bill Graham's card - Wes Wilson's lettering wrapped around Herb Greene's photograph of Grace Slick - advertised the 13th Floor Elevators at the top, over the Great Society and the Sopwith Camel (poster, artist, photo credit, and bill per wolfgangs' BG-25 page). The Elevators, the Texas acid-rock band whose "You're Gonna Miss Me" was already a garage classic, never made it: they were contractually blocked from performing, and Quicksilver Messenger Service filled in (the substitution per the San Francisco Sound history / Corry Arnold). The irony is doubled by the poster's own image - Grace Slick, photographed by Greene, fronting the Great Society, the band she was weeks from leaving to join Jefferson Airplane. So the great Wes Wilson / Herb Greene poster advertises a headliner who didn't play and pictures a singer about to quit the band beneath her. (The printed headliner is the Elevators, not QMS; the substitution, not the poster's face, is the night's real story. COAU lists Aug 26 with QMS and the Great Society and omits the Sopwith Camel and the second night - the poster and catalog carry all three acts across Aug 26-27.)