Power and Knowledge charts a history of three ancient scientiae in the Roman Empire - astrology, medical prognosis, and physiognomy (the art of discerning character or destiny from a person's physique).

Drawing on contemporary approaches in social theory and the philosophy of science, Tamsyn Barton argues that the ancient sciences are best understood in terms of rhetoric, as their practitioners are involved in sociopolitical struggles and their disciplines are rooted in Greco-Roman cultural norms and practices.

Barton provides original readings of an array of texts in order to undermine the distinction between "science" and "psuedo-science" in the study of ancient culture. These include Galen's treatises on pulses and urines, the physiognomical works of Polemo, the astrological writings of Dorotheus of Sidon and Firmicus Maternus, and the "handbooks" used in master-pupil relationships. Barton's study represents the first serious investigation by a modern scholar of this rich variety of ancient writings.

Barton examines the cultural prestige enjoyed by each of the sciences in specific contexts, especially in early Imperial society. She also maps the relation of scientific knowledge to social and political power, demonstrating how each discipline employed internal strategies of analysis and elaboration designed more to preserve knowledge among the elite than to disseminate it.

The conclusions drawn about power and knowledge in the ancient scientiae have implications for the relations between science and politics in any society, and resonate with modern debates as well. Power and Knowledge will interest students of ancient civilizations, historians of science and medicine, students of rhetoric, cultural historians, and anyone interested in the social construction of knowledge.