Does thinking have a history? If there are no necessarily changeless structures to be found in things and in our inquiry into them, then what knowledge of the world and ourselves is possible? In this boldly original and elegantly written study, Joseph Margolis argues for a radically historicized view of history that treats it as both a real process and a narrative account, each a product of continual change. Developing his argument through discussions of such influential philosophers of history and the natural sciences as Vico, Danto, Collingwood, Habermas, Hempel, Popper, Putnam, and Gadamer, he provides a coherent theory of flux and invariance that resolves several deep puzzles regarding human nature and understanding. While maintaining a thorough command of Anglo-American philosophy, Margolis challenges many of its most cherished assumptions and demonstrates the sense in which history and interpretation are one and the same. Exploring one of the master themes of this century, his book offers a novel theory of the human condition whose conclusions and concerns seem certain to inform philosophy in the next century as well.