Physical and chemical studies of the earth and planets along with their surroundings are now developing very rapidly. As these studies are of essentially international charac ter, many international conferences, symposia, seminars and workshops are held every year. To publish proceedings of these meetings is of course important for tracing development of various disciplines of earth and planetary sciences though publishin, g is fast getting to be an expensive business. It is my pleasure to learn that the Center for Academic Publications Japan and the Japan Scientific Societies Press have agreed to undertake the publication of a series "Ad vances in Earth and Planetary Sciences" which should certainly become an important medium for conveying achievements of various meetings to the academic as well as non academic scientific communities. It is planned to publish the series mostly on the basis of proceedings that appear in the Journal of Geomagnetism and Geoelectricity edited by the Society of Terrestrial Magnetism and Electricity of Japan, the Journal of Physics of the Earth by the Seismological Society of Japan and the Volcanological Society of Japan, and the Geochemical Journal by the Geochemical Society of Japan, although occasional volumes of the series will include independent proceedings. Selection of meetings, of which the proceedings will be included in the series, will be made by the Editorial Committee for which I have the honour to work as the General Editor."

Accretion-collision tectonics in mobile belts is one of the most important new topics in solid earth science. A special seminar on this subject, the Oji International Seminar on Accretion Tectonics, was held from the 10th to 16th September, 1981, in Tomakomai, Hokkaido, Japan. It was sponsored by the Japan Society for the Promotion of Science and the Fujihara Foundation of Science, organizers were S. Uyeda, Earthquake Research Institute, University of Tokyo, Amos Nur, Department of Geophysics, Stanford University, and M. Hashimoto, Department of Geology, National Science Museum, Tokyo. More than fifty geoscientists, thirty from Japan and twenty from abroad, met together to present findings from their recent studies and exchange ideas about accretion-collision phenomena in the circum-Pacific mobile belts. Two field days were also spent in the Horokanai area, central Hokkaido, to examine and the Horokanai ophiolite. The the Kamuikotan high-pressure metamorphic rocks latter is a fragment of ancient ocean floor crust that has been obducted onto the Kamuikotan rocks at the time of collision of the Okhotsk Micro-continent with Asia. The seminar was by no means a large congress. However, to the best of our knowledge, it was the first international conference on accretion-collision tectonics. The meeting was highly successful and we believe that it has opened an important new era in the study of plate tectonics.

The ocean floor spreading theory was proposed during 1961 and 62 by Robert Dietz and Harry Hess. This concept was a revolutionary one, and renewed the scientists thoughts on the dynamics of the ocean bottom. Then, for example, the coincidence of the Wadati-Benioff Zone with the subduction zone proposed by new concept was well understood. Further development of the ocean floor spreading theory was the proposal of new concept "plate tectonics" proposed by Xavier LePichon and by a few others during 1967 and 68. This new idea could solve the various conflicts involved in the "ocean floor spreading theory." Therefore, today, scientists understand that the plate tectonics theory was born by the ocean floor spreading theory, which is able to cover the weak points of the latter. D/V Glomar Challenger started her Leg Ion 20 July, 1968 from Orange, Texas to implement the Deep Sea Drilling Project. The timing almost coincided with the proposal period of the plate tectonics. After carrying out a few legs of the drilling operations, the results obtained by D I V Glomar Challenger well proved the rightness of the newly proposed theories of the ocean floor spreading and the plate tectonics. For us, the successful processes started by the ocean floor spreading theory, improved by the concept of plate tectonics and proved by the DSDP results have been a golden monument in the field of earth sciences probably for several centuries.

Physical and chemical studies of the earth and planets along with their surroundings are now developing very rapidly. As these studies are of essentially international charac ter, many international conferences, symposia, seminars and workshops are held every year. To publish proceedings of these meetings is of course important for tracing development of various disciplines of earth and planetary sciences though publishin, g is fast getting to be an expensive business. It is my pleasure to learn that the Center for Academic Publications Japan and the Japan Scientific Societies Press have agreed to undertake the publication of a series "Ad vances in Earth and Planetary Sciences" which should certainly become an important medium for conveying achievements of various meetings to the academic as well as non academic scientific communities. It is planned to publish the series mostly on the basis of proceedings that appear in the Journal of Geomagnetism and Geoelectricity edited by the Society of Terrestrial Magnetism and Electricity of Japan, the Journal of Physics of the Earth by the Seismological Society of Japan and the Volcanological Society of Japan, and the Geochemical Journal by the Geochemical Society of Japan, although occasional volumes of the series will include independent proceedings. Selection of meetings, of which the proceedings will be included in the series, will be made by the Editorial Committee for which I have the honour to work as the General Editor."