Archive of the International Socialist Review, a magazine published by Charles Kerr Publishing Cooperative that was supportive of the direct action oriented 'left-wing' of the Socialist Party and the Industrial Workers of the World. ISR's antiwar stance eventually caused problems with the U.S. government, which revoked its mailing privileges, causing ISR to go defunct.
Ernest Riebe immigrated to the United States from his native Germany sometime around the turn of the 20th century. He became an illustrator and cartoonist for the IWW in the 1910's. His most famous creation was the long running series featuring Mr Block a caricature of a Conservative working man detailing his life and prejudices. Here are a few other images he created.