Chapter 9 Neoclassical growth theory This chapter is an exposition rather than a survey of the one sector neoclassical growth model. It describes how the model is constructed as a simplified description of the real side of a growing capitalist economy that happens to be free of fluctuations in aggregate demand. Once that is done the emphasis is on the versatility of the model in the sense that it can easily be adapted without much complication to allow for the analysis of important issues that are excluded from the basic model. Among the issues treated are: increasing returns to scale (but not to capital alone) human capital renewable and non renewable natural resources endogenous population growth and technological progress. In each case the purpose is to show how the model can be minimally extended to allow incorporation of something new without making the analysis excessively complex. Toward the end there is a brief exposition of the standard overlapping generations model to show how it admits qualitative behavior generally absent from the original model. The chapter concludes with brief mention of some continuing research questions within the framework of the simple model.