John Keynes
John Keynes is widely considered to be the most influential economist of the 20th century. His publication of The General Theory of Employment, Interest and Money in 1936 was groundbreaking. His economic theories advocated the use of fiscal policy to mitigate the effects of severe economic depressions. His theories ushered in a modern era of macroeconomics and Keynesian economics are still the basis for the economic policies of most capitalist governments today.