The Wall Street collapse of September–October 1929 and the Great Depression which followed it were among the most important events of the 20th century. They made the Second World War possible, though not inevitable, and by undermining confidence in the efficacy of the market and the capitalist system, they helped to explain why the absurdly inefficient and murderous system of Soviet communism survived for so long. Indeed it could be argued that the ultimate emotional and intellectual consequences of the Great Depression were not finally erased from the mind of humanity until the end of 1980s, when the Soviet collectivist alternative to capitalism crumbled in hopeless ruin and the entire world accepted there was no substitute for the market. Granted the importance of these events, then, the failure of historians to explain either their magnitude or duration is one of the great mysteries of modern historiography…. For half a century, the conventional, orthodox explanation, provided by John Maynard Keynes and his followers, was that capitalism was incapable of saving itself, and that government did too little to rescue an intellectually bankrupt market system from the consequences of its own folly. This analysis seemed less and less convincing as the years went by, especially as Keynesianism itself became discredited. In the meantime, Rothbard had produced, in 1963, his own explanation, which turned the conventional one on its head. The severity of the Wall Street crash, he argued, was not due to the unrestrained license of a freebooting capitalist system but to government insistence on keeping a boom going artificially by pumping in inflationary credit. More here