Original 1st printing 16 x 22&1/2" concert poster for "the Stanford Summer Rock Concert", an all-day show featuring Quicksilver Messenger Service appearing with the Chambers Brothers, Sons of Champlin, Santana, Creedence Clearwater Revival, Morning Glory and Gypsum Heaps, held at the Frost Amphitheatre in the campus of Stanford University in Palo Alto, CA on 7/28/1968.
 
Artist unknown/not credited, medium-thin flat index stock poster is in very good (B/B+) condition; there is a soft 1&1/2 x 2" stain in the lower left corner (bleed-through from the reverse side), along with a bit of creasing/moisture rippling along the lower left margin, a tiny puncture hole, a tiny bend and a small white spot in the lower right corner, a moderate amount of soft creasing/wear along the right margin, a few well-camouflaged handling/stress creases hiding within the image area and a tiny bit of adhesive on the reverse side, otherwise fine.

 Nifty-looking mid-1968 South Bay multi-act poster with a fantastic lineup and a great period design. First one of these I have come across.