China?s Great Leap Forward (GLF) of 1958-61, a campaign of unprecedented mobilization efforts to achieve rapid industrialization, ended as a catastrophe. National grain production collapsed and a widespread famine claimed millions of human lives. This paper reviews a growing economic literature on this historical crisis. While multiple causes are hypothesized, empirical findings suggest that the collapse of grain production was primarily attributable to a systematic failure in central planning, involving the diversion of agricultural resources to industry and excessive grain procurements that precipitated malnutrition among peasants and decimation of labor productivity. The resulting decline in grain availability, as well as urban bias in China?s food distribution system, became the main culprits of the enormous famine. In light of the Chinese experience, this paper also explores the role of defective planning in the Soviet famines of 1931-3 and 1947.