This Introduction seems to want to begin in an autobiographical register. Recently retired from full-time teaching (at the City University of New York), I naturally gave some thought to producing a collection of articles, written over a number of years and not previously brought together, which might have some claim to lasting relevance (“The collected scientific papers of …” – but that would be begging a question!). With several exceptions, the papers thus collected turned out to have two characteristics. First, they are all written from a political-economic perspective, by which I mean that they seek to grasp and explain the real social relations underlying economic phenomena. To get hold of that substratum of what is normally seen as the “economic” necessarily means to embrace the contradictory – that is, evolutionary, relative, transformational – qualities of social systems and social life. Second, these papers make use of the sort of quantitative formalism that has become a characteristic of modern economic theory. Herein lies an assumption (to which I will return): quantification is not merely a methodological device; it is ontological, a feature of social reality itself – of both the outward, perceived experiences and the inner determinants of those experiences, related both to market forms and to other aspects of the progressive abstraction of human relations that marks the path of social development. The quantitative aspects of the objects of political-economic investigation must therefore be addressed, and gotten right, if political economy itself is to prosper and achieve its objectives. To give this book some semblance of unity and focus, I dropped several papers that do not have a significant quantitative model-building component. The papers that form the ten chapters of the book are what remain. Looking them over, however, one sees another striking feature. The works presented in these chapters have an admirable (or not so admirable, depending on your point of view) characteristic: they are enormously diverse in subject matter. Not to put too fine a point on it: they are all over the place! They range from classical themes in Marxist theory (the law of value; technical change and the falling rate of profit) to topics in microeconomics (Pareto optimality, supply and demand in classical theory, rationing and price control), to macroeconomic stabilization policy, to the theory of the nature and logic of socialism. This, too, requires an attempt at explanation.