The prominent economist known for his theories on capitalism and labor markets is John Maynard Keynes. His ideas, particularly during the Great Depression, emphasized the role of government intervention in stabilizing economies. Keynes argued that active fiscal and monetary policies are essential to mitigate economic downturns and promote recovery. His seminal work, *The General Theory of Employment, Interest, and Money*, reshaped economic thought and led to the development of Keynesian economics, advocating for demand-driven growth. Keynes's influence remains significant in contemporary economic policy debates.