Capitalism is an economic system that is inherently crisis-prone, with alternating periods of frenetic economic expansion and decline, driven by forces that cause it to be unstable, anarchic, and self-destructive. This is as true today as it was over 150 years ago, when Karl Marx and his collaborator Frederick Engels described capitalism in the Communist Manifesto as “a society that has conjured up such gigantic means of production and of exchange, [that it] is like the sorcerer, who is no longer able to control the powers of the nether world whom he has called up by his spells.” Indeed, today’s world of financial panics, stagnation, and long-term unemployment, seems to fit their description better than ever before. This talk provides an introduction to Marx’s theory of capitalist economic crisis, focusing on two basic concepts of Marxism: the “crises of overproduction” and the “tendency of the rate of profit to fall.”