John Maynard Keynes was a renowned British economist born in 1883. He revolutionized economic theory during the early 20th century with his work on macroeconomics and fiscal policy. Keynes is best known for advocating government intervention to stabilize economies during times of recession, proposing the concept of aggregate demand to explain fluctuations in economic output. His seminal work, "The General Theory of Employment, Interest, and Money," published in 1936, laid the foundation for Keynesian economics. Keynes played a crucial role in shaping global economic policies and institutions post-World War II. He passed away in 1946, leaving behind a lasting impact on modern economics.