Original 1st printing 12&1/2 x 19&7/8" concert/event poster for "Zenefit", a benefit performance (for the San Francisco Zen Mountain Center), held at the Avalon Ballroom in San Francisco, CA on 11/13/1966 featuring the Grateful Dead, Big Brother & the Holding Company (featuring Janis Joplin) and Quicksilver Messenger Service.
 
 Designer unknown (photo by Robert Boni), full-color poster image ("Zenefit") is featured in the Art of Rock book on page 184 (plate 2.181).
 
 Medium flat vellum stock poster is in very good to excellent (B/B+ to B+) condition; there are pin holes in the upper left/right corners, along with a bit of light surface dirt/pin-prick scuffing along the top and upper right margins, a small light pin-prick surface stain or two around "Zenefit", a small thin horizontal stress bend extending from the end of "Dead" out to the right center margin, a few light fingerprint smudges/soft handling dings here and there and a nearly-invisible vertical bend above the second "d" of "Dead", otherwise fine.

 Sweet-looking example of this understated (and undervalued, in my opinion) late-'66 Avalon benefit poster with a killer all-San Francisco lineup.