The history of mankind develops from human desires. My research interests cover three basic human desires - food, money and land. In 2008, I published The Price of Rice. The book points out that China was in its primordial stage in market development in the eighteenth century. The market of rice, the single most important commodity, was sporadically integrated. In my another article, “A Desire to Eat Well,” further argued that it was the rise of living standard, instead of the population growth, that stimulated the development of long-distance trade of rice in the Ming-Qing period. My second research interest is money. I have published several articles on the Ming coinage. They showed that Ming merchants used silver bullion, instead of copper coins, to settle the balance of long-distance trade because the bullion was not issued by the state, and therefore its prices in relation to commodities was beyond state control. My third research interest is land management on which I published the book on the land history on Kowloon in 2013, and an edited volume titled Colonial Administration and Land Reform in East Asia in 2017. I believe that the introduction of Western property law of succession as well as the use of triangulation in land survey greatly enhanced the state power over landlords, and thus reshaped the social structure of many parts of Asia.

My research interests cover three basic human desires - food, money and land. In 2008, I published The Price of Rice.