Original 1st printing 14&1/4 x 19&7/8" concert poster for the Daily Flash appearing with Country Joe & the Fish at the Avalon Ballroom in San Francisco, CA on 10/21-22/1966.
Art by Stanley Mouse and Alton Kelley, image is # 31 in the Family Dog/Avalon series. This is the corrected dates/2nd-state edition (OP-2).
Medium-thick flat vellum stock poster is in ULTRA-crisp mint/near mint to near mint (A/A- to A-) condition; aside from a couple of almost-invisible pinch bends in the right margin, it is an UNBEATABLE example of this classic late-'66 Mouse/Kelley Avalon poster.
An EXTREMELY bright specimen without a trace of toning/fading or any other real damage... it looks like it just rolled off the press.