Abstract The subject conference was held May 16-20, 1983, at the Takanawa Prince Hotel, in Tokyo. The primary sponsor was the Japan Atomic Energy Research Institute (JAERI), with cosponsorship or cooperation from the Science and Technology Agency of the Government of Japan, the International Atomic Energy Agency, the Committee on Reactor Physics of the OECD Nuclear Energy Agency, the Power Reactor and Nuclear Fuel Development Corporation (Japan), Japan Nuclear Ship Research and Development Agency, the Atomic Energy Society of Japan, the American Nuclear Society, and consortia of Japanese industrial firms in electric power, nuclear industry, construction, engineering and computer services. H. Ishikawa (JAERI) was Chairman of the National Organizing Committee, and T. Asaoka (JAERI) and T. Hyodo (Kyoto University) were respectively Chairman and Co-chairman of both the National and International Technical Program Committees. Previous conferences in this series, under the title “International Conference on Reactor Shielding,” have been held in Knoxville, Tennessee (1977), Paris (1972), Harwell, U.K. (1967), Studsvik, Sweden (1961) and Cambridge, U.K. (1958).