Original 1st printing 14&1/4 x 20" concert/event poster for the Gathering of the Tribes/Human Be-In, held at the Polo Grounds in San Francisco's Golden Gate Park on 1/14/1967.
 
 This version lists appearances by Lenore Kandel, Timothy Leary, Michael McClure, Allen Ginsberg, Gary Snyder, Richard Alpert, Jerry Rubin, Dick Gregory, Lawrence Ferlinghetti and "all SF rock bands" (which included Jefferson Airplane, Quicksilver Messenger Service, the Charlatans, the Grateful Dead and more).
 
 Art by Stanley Mouse and Alton Kelley with a photo by Casey Sonnabend, image (flyer) is featured in the Art of Rock on page 198 (plate 2.217).
 
 Medium-thick flat vellum stock poster is in good/decent (B to B/B-) condition; there are tack holes and pieces of clear tape in each corner, along with a small burn mark/nip out of the upper left margin, a bit of uneven toning, a soft stain in the lower right margin, a series of soft scuff marks just above "Saturday", a few stray thin bends here and there, light handling wear and a light to moderate amount of surface dirt... definitely looks like it was an original display copy, that's for sure.

 Overall, a pretty nice-looking moderately-used 1st printing example of this oft-requested poster from one of the epochal events in 1960's counterculture history. Check out 26 minutes of coverage of the event HERE:
 
https://www.youtube.com/watch?v=HTGyFgyB5Q8