This book explores Aristotle's theory of stasis, a word usually translated to mean "revolution", "civic disorder", or "sedition". It examines Aristotle's writings on stasis, especially Book 5 of the Politics, within the tradition established by ancient Greek poets, medical writers, philosophers, and orators, who held that the root sense of stasis was in fact nosos, or "disease". Aristotle's theory of the causes of stasis is presented in a cohesive manner, as factors that can account for political disease within the entire range of diverse constitutions. Aristotle is shown to have proceeded from the standpoint that the polis had to be cast in a mode of political friendship, what the Greeks called homonoia or "political friendship", and that when other standards for friendship such as wealth or liberty are practiced to an extreme, then the function of the polis may be "arrested". The telic functions of the polis are replaced by disordered "movements" whose paralyzing effect -- as evidenced by transformations in values and language, and the pursuit of private-interest ends -- is typical of a dysfunctional condition that often ends in senseless violence and civil war.