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 decent/used (B/B-) condition; this example has a semi-flattened horizontal center crease, tape marks/staple holes in all four corners, a bit of toning, a couple of tiny edge nip tears, slightly rounded corner-tips, a bit of pen scratch ("1966" in blue ballpoint) on the reverse and a few tiny pin-prick surface spots hiding within the image area, otherwise it is a very presentable-looking example of this classic late-'66 Mouse/Kelley poster from the Avalon.