This poster was a winner of the “No More War” poster contest organized by Avant Garde magazine, and was published in Avant Garde, volume 5, along with the other winning posters.
The design is extremely simple, composed as a two-word anti-war petition/statement/form (set in tightly-spaced Franklin Gothic) with a field of lines for signatures. The first two lines have the signatures of the poster’s designers, Billy Apple and Robert Coburn.
The red field surrounding the poster does not seem to be part of the original design but just how the poster was shown in Avant Garde.
More recently, the poster was revived as street art in London (though with a different typeface) by Benjamin Shey Lee.