Official promoter-issued 2nd printing (RP-2 in the Eric King guide) 14&3/8 x 20&1/2" concert poster for early rock & roll pioneer Bo Diddley appearing with Big Brother & the Holding Company (featuring Janis Joplin) at the Avalon Ballroom in San Francisco, CA from 8/12-13/1966.
 
 Art by Stanley Mouse and Alton Kelley, image ("Earthquake") is # 21 in the Family Dog/Avalon series.
 
 Medium-thin flat index stock poster is in near mint to excellent (A-/B+ to B+) condition; just a touch of edge creasing, plus a pair of tiny nip tears and a bit of minor creasing along the top left margin, otherwise fine.

 Nice-looking example of this early Mouse/Kelley-designed Avalon Ballroom poster.