The title of this monograph, Brain Tumor Research and Therapy, is the name of the Conference itself, which had its inaugural meeting in the United States in 1975 andhas since progressed to the international scale. In Japan, the first conference ofits kind was organized by Dr. Takao Hoshino and me and was held at Nikko in 1980, hence its name, the Nikko Conference on Brain Tumor Research and Therapy. Though it started as a small, closed meeting, the conference has grown considerably, and in 1992 it was reorganized as the Japanese Conference on Brain Tumor Research and Therapy and was opened to all neurosurgeons and neuropathologists interested in the study of brain tumor problems and who are participating in this field. The main purpose of the Conference on Brain Tumor Research and Therapy is the candid and informed discussion of the most up-to-date developments in basic re search and clinical treatment of brain tumors. The 3rd Japanese Conference on Brain Tumor Research and Therapy was held at Nasu (Tochigi Prefecture), Japan, in No vember 1994. It was a great honor to welcome many distinguished guests from over seas who kindly attended each session and made valuable contributions.