THEMATIC EVOLUTION IN AMERICAN STUDIES Zhang Tao(126) Faced with the rather inclement natural environment before the industrial revolu tion, American settlers were preoccupied with their survival and development. Th ey could not devote themseves much to the tracing of their cultural tradition un til the beginning of this century. Along with the industrialization, exploring t he origins of American culture and defining cultural interrelations among indivi duals, society, history, literature and so forth have become fundamental tasks o f American studies in this century. This practice has hereafter undergone the ev olution of three main themes, namely the combination of literature with history, myths and symbols, and pluralism.