Original 1st printing 14 x 20" poster for a benefit for the Both/And nightclub (a tiny jazz club on Divisadero Street), held at the Fillmore Auditorium in San Francisco, CA on 9/11/1966.
Participants included: Elvin Jones and Joe Henderson, Jon Hendricks Trio, Big Mama Thornton, Denny Zeitlin Trio, Jefferson Airplane, Great Society (featuring Grace Slick), Wildflower and (not listed but definitely appeared) the Grateful Dead.
Artist unknown/not credited, image is not part of the numbered Bill Graham/Fillmore series (this show falls on the day after the BG 27 show) and appears in the Art of Rock on page 151 (plate 2.74) in the "Fillmore Auditorium Benefits" chapter.
Medium flat vellum stock poser is in very good to excellent (B/B+ to B+) condition; a set of tiny pin holes (all four corners and a couple hiding within the image area), a light to moderate amount of creasing in the right center margin (mostly pressed flat), a soft diagonal bend in the lower right corner (about 3"), a couple of very soft bends hiding within the image area and a whisper of toning, otherwise fine.
An overall SUPERB-looking example of this very early (1966) 1st printing Fillmore benefit poster, read more about the event (including reviews) HERE: