So this is kind of exciting.
All issues of Avant Garde Magazine have been made available for online viewing in their entirety.
It ran from 1968-71, 14 issues in total, published by the controversial Ralph Ginzburg.
Not universally beloved; there was particular loathing from some of the font fanatics (not to say fetishists) of the world (and support from others) against Avant Garde typeface created by art director Herb Lubalin.
You can view the issues online here, or download them courtesy the brilliant Internet Archive here.