Original 1st printing 13&7/8 x 19&7/8" concert poster for rock n' roll pioneer Bo Diddley appearing with Big Brother & the Holding Company (featuring Janis Joplin) at the Avalon Ballroom in San Francisco, CA on 8/12-13/1966. Art by Stanley Mouse and Alton Kelley, image ("Earthquake") is # 21 in the Family Dog/Avalon series. Medium flat vellum stock poster is in very good to excellent (B/B+ to B+) condition; a set of tack/staple holes (all four corners), light handling, a minor amount of surface wear, a trace of toning and a couple of minor edge dings, otherwise fine. An overall VERY nice-looking gently used example of this early 1st printing Mouse/Kelley poster from the Avalon.