English economist whose ideas fundamentally changed the theory and practice of macroeconomics and the economic policies of governments. 

In his 1936 book, The General Theory of Employment, Interest and Money, Keynes spearheaded a revolution in economic thinking, challenging the ideas of neoclassical economics which held that free markets would, in the short to medium term, automatically provide full employment, as long as workers were flexible in their wage demands. He instead argued that in the short to medium run aggregate demand determined the overall level of economic activity and that inadequate aggregate demand could lead to prolonged periods of high unemployment.

He built on and greatly refined earlier work on the causes of business cycles, and is widely considered to be one of the most influential economists of the 20th century and the founder of modern macroeconomics.

Link to the History of Economic Thought Website

A Keynes for All Seasons The Economist

Obituary of Keynes 1946 The Economist