John Maynard Keynes was a renowned British economist whose groundbreaking work revolutionized economic thought in the 20th century. Born in 1883, he became a pivotal figure in macroeconomic theory, particularly through his seminal book, "The General Theory of Employment, Interest, and Money," published in 1936. Keynes advocated for government intervention to mitigate the adverse effects of economic recessions and depressions, laying the foundation for modern Keynesian economics. He also played a key role in shaping post-World War II economic policies, contributing to the establishment of institutions like the International Monetary Fund. Keynes passed away in 1946, leaving a lasting legacy on global economic policy.