Approximately 150 engineers and scientists from 15 countries attended the International Symposium on Land Subsidence held at Tokyo, Japan, from September 17 through 24, 1969. The symposium was sponsored by Unesco, the International Association of Scientific Hydrology (IASH), the International Society for Soil Mechanics and Foundation Engineering (ISSMFE), the Science Council of Japan, the Tokyo Metropolitan Government, and the Japanese National Commission for Unesco. The symposium was organized within the framework of the International Hydrological Decade (IHD). All papers sessions were held at the conference center of the Akasaka Prince Hotel in Tokyo.