Original 1st (only) printing 14 x 20" concert poster for 1960's pop-folk-rockers the Grass Roots (1st version) appearing along with the Sons of Adam and Big Brother & the Holding Company (before Janis Joplin joined) at the Avalon Ballroom in San Francisco, CA on 4/29-30/1966* (show canceled).

Art by (and SIGNED in pencil by) Wes Wilson (central image borrowed from Franz (Von) Stuck), image ("Sin Dance") is # 6 in the Family Dog/Avalon series.

 Medium-thick flat vellum stock poster is in VERY sharp/crisp mint/near mint to near mint (A/A- to A-) condition; aside from a nearly-invisible pinch bend in the left center margin and a negligible degree of surface wear, it is an absolutely UNBEATABLE ARTIST-SIGNED example of this early Avalon poster.