...Never a member of the counterculture himself, Crumb created a large and diverse body of work during the late 1960s and early 1970s. To a large extent he defined underground comics. He produced a number of solo books between 1968 and 1971,including Zap, Big Ass, Despair, Uneeda, Mr. Natural, and many others.
His subjects, the preoccupations of the rebellious youth of the 1960s, were to become the staples of the genre: sex (Crumb's treatments of it were so explicit that they led to a famous censorship trial), drugs, and the decay of spiritual values. His pen was merciless. He spared nothing and no one, including himself. Among his most enduring creations were the archetypal "straight" Whiteman; the dumb hippies yearning for spiritual enlightenment (but unwilling to give up their TV), Flakey Foont and Shuman the Human; and the sublimely cynical guru, Mr. Natural.
(http://www.askart.com/artist_bio/Robert_R_Crumb_Crumb/64739/Robert_R_Crumb_Crumb.aspx)