Warren Samuels interprets Vilfredo Pareto's Treatise on General Sociology in terms of a general equilibrium model of policy. Three themes and one conviction run throughout the study. The first is a model of policy making involving three sets of variables: power, knowledge, and psychology. The second is a general equilibrium approach to the study of these variables emphasizing their fundamental interdependence. The third is the importance of Pareto's work. Pareto is one of the few individuals whose work has had enormous influence in at least three social sciences in the twentieth century: economics, sociology, and political science. Despite Pareto's attempt in the Treatise to produce a general sociology encompassing all of these sciences (as well as psychology), his work has been treated almost completely from the perspectives of the individual disciplines. This volume's interpretation is consonant with Pareto's intention in the Treatise, namely, to provide a general equilibrium model of the total socio-politico-economic decision-making or policy process. The book is directed at those who comprehend these as processes whose structure, conduct, and performance are a function of complex decision making. Social scientists and policy analysts have moved beyond models that solve problems in the abstract, without working them out through policy making in the real world. The approach outlined here is important to those who are interested in pursuing the working rules of law and morals that govern the distribution and exercise of power as well as the exercise of power that governs the development of these rules.