Original 1st printing 14&7/8 x 19&7/8" concert poster for Quicksilver Messenger Service appearing with Big Brother & the Holding Company (featuring Janis Joplin) and Country Joe & the Fish at the Avalon Ballroom in San Francisco, CA from 11/25-26/1966.
Art by Victor Moscoso, image is # 36 in the Family Dog/Avalon series (this is the OP-1 version with the dark "brick" red ticket outlet strip).
Medium-thick flat vellum stock poster is in very good to excellent (B/B+ to B+) condition; there are tack holes in each of the four corners, along with a bit of edge toning and a couple of tiny nicks scattered around the outer margin area, a couple of nearly-invisible handling dings hiding within the image area and a light amount of streaking on the purple pass of ink, otherwise fine.
A very nice-looking 1st printing example of this early Moscoso Family Dog image. Check out the original radio spot for the show!