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 (FD-36-OP-1 in the Eric King guide).

 Medium-thick flat vellum stock poster is in excellent (B+) condition; aside from a tiny 1&1/2" bend in the lower left corner tip, a very thin vertical crease running along the right margin/border and a couple of minuscule edge/corner-tip pressure dings, it is a SUPERB example of this early Family Dog poster with a great all-Bay Area lineup.