Original 1st printing 14&1/8 x 20" concert poster for Chicago blues legend Howlin' Wolf appearing with Big Brother & the Holding Company (featuring Janis Joplin) at the Avalon Ballroom in San Francisco, CA from 9/23-24/1966 (*show was canceled). 
 
 Art by Stanley Mouse and Alton Kelley, image is # 27 in the Family Dog/Avalon series. (OP-1 in the Eric King guide, the version with the orange-border lettering)
 
 Medium-thick flat vellum stock poster is in good (B) condition; this example has VERY light red/orange inking and a slightly off-register green pass of ink (probably from the end of the print run), along with a couple of tiny hairline edge/corner tip bends, a few stray soft handling dings hiding within the image/outer margin area and there is a bit of uneven toning (and a "Lorin Gillette Distributor" stamp on the reverse, but otherwise it's in pretty good shape- the light inking is really the only prominent cosmetic issue, it's actually physically quite nice.

Very presentable original 1966 Mouse/Kelley concert artifact from the Avalon.