Proceedings of the twenty-first EGS users' meeting in Japan

The meeting has been hosted by the Radiation Science Center. More than 100 participants attended the meeting. The meeting was divided into two parts. Short course on EGS was held at the first half of the workshop using EGS5 code. In the later half, 10 talks related EGS were presented. The talk covered the wide fields, like the medical application and the calculation of various detector responses etc. These talks were very useful to exchange the information between the researchers in the different fields. This issue is the collection of the paper presented at the title meeting. The 10 of the presented papers are indexed individually. (J.P.N.)