Milton Glaser designed this poster to coincide with the May 10, 1969 International Grape Boycott. Beneath the image of a bunch of grapes, doubling as a deathly skull, is a quote by Cesar Chavez, respected Chicano civil rights leader and labor activist.
“Don’t eat grapes” uses Helvetica Black. On the bottom of the poster, the quote by Cesar Chavez is set in what looks like News Gothic. The header uses Lightline Gothic — which is similar to News Gothic, but can easily be discerned here because of its M with an apex that does not touch the baseline.
This piece can be seen at Letterform Archive, a San Francisco nonprofit center for inspiration, education, and community with a large collection of posters.