The General Theory of Employment, Interest, and Money

This is the book that revolutionized modern economics. Keynes demolishes classical economic theory and builds something far more relevant to the real world. His insights into unemployment, monetary policy, and market psychology remain startlingly relevant today. While it's not an easy read, mastering Keynes's ideas will give you a framework for understanding everything from financial crises to government policy. Essential for anyone who wants to understand how the modern economy actually works.