John Maynard Keynes is remembered for his contributions to dynamic economic theory, particularly through his advocacy for government intervention in the economy. His groundbreaking work during the Great Depression emphasized the need for active fiscal and monetary policies to stimulate demand and pull economies out of recession. Keynes challenged classical economic theories that advocated for minimal government involvement. His seminal work, "The General Theory of Employment, Interest and Money," laid the foundations for Keynesian economics, which influenced many governments’ policies worldwide in the mid-20th century. His ideas shaped modern macroeconomic thought and remain relevant in discussions on managing economic crises today.