A pioneering anthropologist, social theorist, railroad lawyer, and advocate for Native Americans, Lewis Henry Morgan was the only American to be cited by Darwin, Marx, and Freud. By many accounts, he was the most influential American social scientist of the nineteenth century. Morgan traced humanity's progress from life among a primary group to one in an increasingly impersonal civilization - from primitive cave to civilized parlor - and along the way explained the meaning of modernity and the meaning of America. For Morgan, they were one and the same.Daniel Noah Moses has written the most complete biography of this prominent intellectual to date - and the first in nearly half a century - tracing his career and documenting in detail his worldwide influence. Although Morgan is best known among anthropologists, Moses reveals to a wider readership his life and accomplishments as an important American thinker who considered the United States the embodiment of the Enlightenment and a model for the world.Moses presents Morgan's life in great detail, with facts that will surprise even those who think they know him. From his early work with the Iroquois to his defense of American capitalism to his strange posthumous career among international communists and American leftists, Moses weaves together the diverse strands that made up the rich tapestry of this singular life. He locates Morgan's American voice within a tradition of trans-Atlantic social theory dedicated to understanding the spirit that motivates modern societies. In showing how Morgan reflected the interplay between Christian, classical, and liberal traditions, Moses delves into the role of such concepts as ""savagery,"" ""barbarism,"" the ""primitive,"" ""progress,"" and ""civilization"" in nineteenth-century social theory and in the broader American culture. And he tells how even today Morgan's influence is felt among environmentalists, anarchists, feminists, and other social visionaries.Morgan explained how humans evolved beyond nature to both the splendor and squalor of the Industrial Age and offered an unprecedented analysis of the interplay between family, property relations, the state, and the human mind. ""The Promise of Progress"" will spark the imagination of anyone who worries that progress has outstripped the human capacity to live together, allowing readers to better understand the relationship between the American emphasis on consumption, the buried riches of the American dream, and the possibilities for our future.