Since 2008, the world economy has been struct by a major catastrophe, that has spread from the financial markets to thedepths of the production framework, resulting in a lack of investment, massive unemployment, persistent inflation, etc.Despite the attempts by business and governments to mend the fractured economies, some of the effects are still visibleand re-emerge even more persistent after the Covid crisis and the outburst of the war in Ukraine. However, crises of thissort are not rare in the system, neither can be explained as mere failures. On the contrary, inherent mechanisms seem tobe at play, which periodically but systematically bring the economy to the edge of collapse. In this course, we attempt tounveil these mechanisms. We will explore (a) the main forms of short- and long-run fluctuations of the capitalist system,(b) the main theories attempting to explain them (Keynesian, Schumpeterian, institutionalist, underconsumptionist,Marxist, etc.), (c) the history of the phenomenon (with main emphasis on the major events of the 19th, 20th and 21stcentury), and (d) the possible outcomes of the current crisis for the society, the economy and the environment.