The problem of e?cient or optimal allocation of resources is a fundamental concern of economic analysis. The theory of optimal economic growth can be viewedasanaspectofthiscentraltheme,whichemphasizesingeneraltheissues arising in the allocation of resources over an in?nite time horizon, and in p- ticular the consumption-investment decision process in models in which there is no natural "terminal date". This broad scope of "optimal growth theory" is one which has evolved over time, as economists have discovered new interp- tations of its central results, as well as new applications of its basic methods. The purpose of this handbook is to provide surveys of some signi?cant results of the theory of optimal growth,as well as the techniques of dynamic optimi- tion theory on which they are based. Armed with the results and methods of this theory, a researcher should be in an advantageous position to apply these versatile methods of analysis to new issues in the area of dynamic economics, as well as to contribute to the further development of the mathematical te- niques of optimization over time. The survey included in this volume all have as a common starting point the seminal contribution of Frank Ramsey (1928).