The 1930s marked the first stirrings of the science of macroeconomics, founded by John Maynard Keynes as he tired to understand the economic mechanism that produced the Great Depression. After World War 2, reflecting both the increasing influence of Keynesian views and the fear of another depression, the U.S Congress formally performance. It enacted the landmark Employment Act of 1946. Since the 1946 Employment Act, the nation's priorities among these three goals have shifted; but in the United States, as in al market economics, these goals still frame the central macroeconomic questions: 1. Why do output and employment sometimes fall, and how can unemployment be reduced? All market economies show patterns of expansion and contraction known as business cycle. 2. What are the sources of price inflation, and how can it be kept under control? Economists have learned that high rates of price inflation have a corrosive effect on market economics. 3. How can a nation increase its rate of economic growth? Above all, macroeconomics is concerned with the long run prosperity of a country. Over a period of decades and more, the growth of a nation's productive potential is the central factor in determining the growth in its real wages and living standards.