The birth of macroeconomics as a separate branch within economics can be dated to the publication in 1936 of John Maynard Keynes's The General Theory of Employment, Interest, and Prices. Prior to Keynes's time, economists had studied the behavior of the entire economy and placed special emphasis on understanding the role of money and the general level of prices.

But the modern field of macroeconomics, with its stress on understanding why economies experience episodes like the Great Depression and why employment and production grow an fluctuate over time, begins with Keynes.

Many of the government policies and programs, such as Social Security and federal insurance for bank deposits, grew out of the experience of the 1930s. Perhaps the most important legacy is the general acceptance of the notion that governments are responsible for ensuring that periods like the Great Depression never reoccur.