Official promoter-issued 2nd printing 23&3/4 x 10&1/4" concert poster for Big Brother & the Holding Company (featuring Janis Joplin) appearing with the Oxford Circle on 8/5/1966 and rock & roll pioneer Bo Diddley appearing with the Sons of Adam on 8/6/1966, both shows held at the Avalon Ballroom in San Francisco, CA.
Art by (and SIGNED in black flair pen by) Stanley Mouse (with Alton Kelley), image ("Dollar Bill") is # 19 in the Family Dog/Avalon series.
Medium flat index stock poster is in very good (B/B+) condition; there are a number of semi-pronounced thin bends/creases and handling dings scattered along the lower left, upper right and left/right center margins, a couple of thin diagonal bends in the lower left/upper right corners, a series of thin stress bends hiding within the image area and a small pencil scratch on the reverse, otherwise fine.
Nice-looking ARTIST-SIGNED example of this classic Family Dog image.