Reacting to the tradition which has reduced rhetorics to summaries of rules and principles, this book presupposes that Plato's "Phaedrus," Aristotle's "Rhetoric," and Cicero's "De Oratore" cannot be reduced to summary information or pedagogical advice. The book considers that these works, on the contrary, along with later renegade theories of rhetoric, identify rhetoric with inconclusiveness and ambiguity. Divided into three chapters and an afterword, the book begins with a discussion of the major figures of classical rhetoric--Plato, Aristotle, and Cicero--asserting that they define and demonstrate rhetoric as the elaboration of ambiguity. The second chapter examines the rhetorics of Michel de Montaigne, Giambattista Vico, and David Hume, noting that although they had only slight influence in the history of rhetoric, they continued the spirit of questing and ambiguity by resisting a positivistic epistemology that exalted knowledge-as-information. Finally, the third chapter discusses Hugh Blair's theory of reading and the most radical and controversial 19th century challenges to his "plain style" prescriptions--George Byron's "Don Juan" and Thomas DeQuincey's essays on rhetoric and style. The afterword considers the modern critical theories of Kenneth Burke, Clifford Geertz, Paul Feyerabend, and Jacques Derrida, and presents some general propositions, or "lessons of history," for teachers of rhetoric. (Four pages of notes and 104 references are appended.) (MM)