According to the modern economists there are mainly two approaches to the study of the science of economics viz Micro economic approach and Macroeconomic approach. [Formerly the two approaches were known as Price Theory and Income Theory].
The terms Micro economics and Macro economics were coined by Ragner Frish of the Oslo University of Norway in the 1933, have now become a universal phenomenon adopted by all economists all over the world. This division of economic theory into two separate parts ie micro economics and macro economics has gained much importance.
The origin of these two approaches to economic analysis can be traced to the era of classical economists.
Micro economics dealing with the problem of determination of value started with Adam Smith and found favour in the writings of David Ricardo, John Stuart Mill etc, but was developed and popularized by Dr Alfred Marshall. This is because most of Marshallian analysis is based on Micro economic approach.
Macro economic analysis did prevail even before the evolution of Micro economic. The English merchants, were concerned with the economic system as a whole. The Marginalists, who succeeded the classical economists, relegated Macro economics to the background. Their field of enquiry was micro in nature.