Because issues discussed in the introductory chapter were primarily methodological, it is appropriate for these final words to summarize some main points of content of the book. In addition, because the line that defines where a book of this type stops must be drawn somewhat arbitrarily, the reader's indulgence is asked if some mention is made of current work not reported upon in previous chapters, but that bears upon the issues.

The task of Chapters 1 through 3 is to place the Marxian notions of economic reproduction and exploitation into a general equilibrium context. In most mathematical treatments of Marxian economics, only the production side of the economy is studied, and it is simply asserted that a certain price vector (the vector that equalizes profit rates across sectors) is the “equilibrium” vector. This formulation is inadequate, because no specific behavior of capitalists and workers is stipulated, with respect to which equilibrium has been defined. An equilibrium of an economy is a situation where the optimizing behavior of all individuals aggregates to social behavior that is consistent; clearly, then, the definition of equilibrium requires a prior specification of what the behavior of individuals is. This may seem a small point; it is not, as can be seen from common disagreements or confusions that have emerged between Marxists and neoclassicists concerning Marxian equilibrium. For instance, a neoclassicist asks how there can be an “equilibrium” with a positive rate of profit in an economy with constant returns to scale.