Original 1st printing 5&1/4 x 8" double-sided concert/event handbill for the Grateful Dead, Big Brother & the Holding Company (featuring Janis Joplin) and Quicksilver Messenger Service appearing together in a benefit performance (for the San Francisco Zen Mountain Center), held at the Avalon Ballroom in San Francisco, CA on 11/13/1966.
 
 Designer unknown (photo by Robert Bono), full-color poster image ("Zenefit") is featured in the Art of Rock book on page 184 (plate 2.181).
 
 Medium-thin flat stock handbill is in very good (B/B+) condition; there is a light amount of handling wear/soft creasing throughout the piece, along with a tiny pull in the right center margin, a couple of lightly creased/soft corner tips, a few tiny pin-prick surface spots scattered around the outer margin area, a couple of stray edge dings and a VERY soft diagonal bend in the lower left corner, otherwise it is a pretty nice-looking example of this VERY early Grateful Dead/Janis benefit handbill from the Avalon.