Original 1st printing 14 x 20&1/4" concert poster for Quicksilver Messenger Service appearing with Big Brother and the Holding Company (featuring Janis Joplin), Blue Cheer and Mount Rushmore at the Avalon Ballroom in San Francisco, CA from 6/29-7/2/1967.
Art by (and SIGNED in pencil by) Victor Moscoso, image is # 68 in the Family Dog/Avalon series.
Medium-thin flat index stock poster is in BEAUTIFUL mint/near mint to near mint (A/A- to A-) condition; aside from a stray fingerprint or two hiding within the image area, this is a VERY crisp/clean example of this mid-'67 1st printing Avalon poster with an incredibly hard-to-read Moscoso design and an eye-searing color scheme.