The chapter provides an overview of the main areas of research in history of economic thought, that correspond to a classic division of phases of development of the economics discipline from its origins to its present state. Following the Journal of Economic Literature classification, the evolution of economics is subdivided into two phases—namely, history of economic thought through 1925 and since 1925; a shorter third part on recent developments is added to this basic scheme. Focus is on what each period contributed to the study of three foundational issues in economics, namely, the theory of individual economic behavior, the market mechanism as a coordinating device, and the respective roles of markets and governments in the regulation of economic systems. Reflection on these issues has progressively formed economists’ understanding of society and has then been extended to a broad range of social phenomena, from monetary and financial matters to health and the environment. These very issues have been the object of major controversies that have divided economists into different schools and have ultimately shaped the history of the discipline. In outlining these developments, similarities and differences between past and present theories are emphasized.