Original 1st printing 8&1/2 x 9" concert flyer for the Sparrow (proto-Steppenwolf) appearing at the Matrix in San Francisco, CA from 4/28-30/1967. 
 
 Artist unknown/not credited (looks like Leidenthal), thin flat pulpy stock flyer (YELLOW stock) is in very good to excellent (B/B+ to B+) condition; there are flattened horizontal/vertical folds (item was folded into 1/4ths and subsequently pressed out), plus a soft stray pinch ding or two hiding within the image area and a couple of tiny corner-tip dings, otherwise it is a GREAT-looking example of the YELLOW stock version of the always-popular "gooney bird" Matrix flyer.