Original 1st printing 14&1/4 x 20" concert/event poster for the 1/14/1967 Gathering of the Tribes/Human Be-In, held at the Polo Grounds in San Francisco's Golden Gate Park.
This version lists appearances by counterculture heroes 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 very good (B/B+) condition; there are tack holes in each corner, a thin vertical tape residue mark/shadow going down the middle of the sadhu's beard, a trace amount of handling and an ULTRA-subtle moisture wave to the paper, otherwise fine.
REALLY NICE-looking 1st print example of this classic image from one of the most significant events in 1960's counterculture history. Check out 26 minutes of coverage of the event HERE: