Money plays a vital role in the determination of income and employment. The basic problems of macroeconomics are the determination of income, output, employment and the general price levels, including the determination of the long-run rate of growth of income. As far as the growth theory is concerned, the supply and demand for money have been largely ignored until recently, yet all but the very simplest short-run income and price level determination models have a money market included in them.
As such, money becomes an economic force in its own right, which under certain circumstances, powerfully affects economic activities. This is the main subject matter of monetary economics. Monetary theory is that branch of economics which aims at discovering and explaining how the use of money in its various forms affects production, consumption and distribution of goods. As a matter of fact, the advocates of monetary theory plead that a large number of factors affect the volume of production, consumption and distribution. To them, money is no more a veil, a medium to facilitate exchange of goods: but something more vital, more crucial and more important, which affects the general level of economic activity.