The obstacle facing anyone who wishes to discuss any limitations of using game theory to build economic models or even criticize game theory or game-theoretic models is the bifurcation of the proponents. On the one hand, we have the economists who are building game-theoretic models in the hopes that they can overcome one of the short-comings of both Marshallian partial-equilibrium analysis, which looks only at the behaviour of singular, price-taking individuals who are just minding their own business, and those who complain about Walrasian general-equilibrium models, which do not recognize the diversity in an economy or the interaction between individuals beyond buying and selling in the markets. On the other hand, we have the mathematics-oriented game theorists who lead the way in game-theoretic analysis and who, regardless of realism, are willing to assume anything that helps them construct their proofs or find solutions for their equilibrium models. Most of the critical questions I discussed at the end of Chapter 3 are the result of these mathematics-oriented assumptions. This chapter will focus on whether the mathematical devices and assumptions that have been invented to answer those questions are as useful as game theorists think or as limited as some critical economic model builders think.