It has taken me a number of years to complete this book, but for good reasons. In the early 1990's, when I began this project as my doctoral dissertation at the Columbia University School of Law, preparations for the United Nations Conference on Environment and Development were well under way. With many international actions being taken for the convening of the Conference, it was envisaged that international environmental law was likely to proliferate. In the years that followed, this anticipation proved far-sighted, as new legal instruments on environmental protection were so overwhelming that it became difficult to keep pace with them. Although my research work had to be continually updated, these legal developments have greatly enriched my study on international liability for transboundary damage.

Meanwhile I had finished my residence requirement at Columbia Law School and returned to China, proceeding with the dissertation while working. As I was taking on greater responsibilities in the Legal Department of the Foreign Ministry, however, the project frequently had to give way to urgent office matters. After two years of hard work, I finally passed my oral defense in 1995 and set about revising the dissertation for publication. At this stage, developments in China led me to reflect on some of my original thinking on the study, particularly about the relationship between environment and development.

After seventeen years of rapid economic growth, China was faced with seriously deteriorating environmental conditions.