The present book is the result of a quantitative study on agricultural production during the Qing dynasty. My interest in this topic began in the late 1980s, when I was studying for my doctorate in the Department of Economics at the Graduate School of the Chinese Academy of Social Sciences. At that time, the discipline of “cliometrics” had just been introduced from the West (in particular from the USA), causing a minor boom in studies among Chinese economic historians.1 Under the influence of this trend, in my doctoral dissertation, entitled Study on the Peasant Economy in the Early Qing Period, I not only described and analysed the peasant economy in terms of its production relations (e.g. land tenure, tenancy, rent forms, and the like), I also made quantitative estimates of its productivity during the period. In the dissertation, using the large amount of historical data I had collected during my three years as a doctoral candidate, I estimated China’s land area under cultivation, its grain yield (total output and output per unit of area), and its agricultural labour productivity on the eve of the Opium War, which broke out in the early 1840s. These results were later successively published during the late 1980s and early 1990s.