Price theory has always been and still is at the heart of economic theory. For the past two and a half centuries, economic theorists have been trying in many different ways to understand and explain the determination of relative prices between goods and services. Usually at a very high degree of sophistication, the profession's brightest minds have been slowly building up this crucial stepping-stone of the entire field of economics analysis. Concentrating exclusively on the "primary" literature, this multi-volume set brings together for the first time the most significant text of these successive and often conflicting intellectual endeavours to solve this most difficult of all economic issues. Though fully aware of the sometimes fundamental "theoretical" differences between these various approaches, this choice of texts attempts to suggest an interpretative framework linked to the common "method" used by successive schools of thought. Described in the crudest possible way, for the past 250 years, economists have been working with one version or another of the so-called "gravity theory": long-run, natural or equilibrium reasoning investigates the logical state "determination" of relative prices by theorists attempting to understand the fundamentals of market (or non-market) economies; short-run, market or disequilibrium reasoning scrutinizes the "formation" of relative prices, that is, the dynamic process (including, possibly, institutional set-ups) necessary to bring about these natural/equilibrium prices. Even when some modern-day theorists studiously ignored this century-old gravity principle, their approach cannot h From Aristotle's theory of exchange down to the Arrow-Debreu-MacKenzie model of the 1950s, these volumes provide modern economists as well as historians of economic thought with classic texts in the doctrine of "just price", the land theory of value, the cost-of-production theory of value, the labour theory of value, and finally, the marginalist revolution at the root of most modern developments in partial and general equilibrium analyses.