Instrumental in the formation of the underground comics scene in the 1960s and 1970s, R. Crumb (b. 1943) has helped challenge and expand the boundaries of the graphic arts and redefined comics and cartoons as countercultural art forms. Widely circulated and celebrated, Crumb's published imagery, such as his comic strips Fritz the Cat, Mr. Natural, and Keep on Truckin', offers a mordant satirical critique of modern society.