The General Theory of Employment, Interest and Money – John Maynard Keynes

"The difficulty lies, not in the new ideas, but in escaping from the old ones."

Writing during the Great Depression, Keynes revolutionized economics by arguing that free markets do not always self-correct to full employment. He proposed that government intervention through fiscal policy (spending and tax breaks) is necessary to manage aggregate demand and prevent economic collapses.

This book created the field of macroeconomics. Keynes's ideas shaped the economic policies of the Western world for decades after WWII and remain central to debates about how governments should respond to financial crises.