"Labor is a necessary condition of all human existence, and one which is independent of the forms of society. It is through all the ages a necessity imposed by nature itself, for without it there can be no interchange of material between man and nature -- in a word, no life."
"Hugo Gellert was a communist, graphic artist, cartoonist, muralist and painter born in Hungary in 1892. After coming to the U.S. in 1906, he became a leading contributor of art work to progressive journals such as The Masses and Liberator, and was the author of 3 books. He played a leading role in many Popular Front arts organizations such as: the Mural Artists Guild of the United Scenic Painters, the Artists Coordinating Committee for the New York World's Fair and Artists for Victory; he was also involved with the Hungarian-American anti-fascist group, the Anti-Horthy League." Gellert died in 1985.
The top 2 images come from Aesop Said So 1936.
The rest come from Karl Marx' 'Capital' in Lithographs 1934.
Both are online at the 'Graphic Witness - Visual Arts & Social Commentary' website (which has a lot of other interesting material).