Illustrator Ian Whadcock switched me on to Shahns book 'The Shape of Content' that has influenced my approach to teaching as well as the subject enormously. Shahn was an artist who spoke to the world. A man of uncompromising beliefs, he became the most popular artist of his age – his work was on the cover of Time as well as in the Museum of Modern Art.
Shahn came to prominence in the 1930s with "The Passion of Sacco and Vanzetti," a politically pointed series about the Italian anarchists who many believed were framed for murder. He went on to paint murals and take photographs for the government during the New Deal, and to become a successful painter and commercial artist.
Check out a good site that gives context and overviwe to his oevre.