Computer technology has developed remarkably in the field of neurosurgery during the past 10 to 20 years. Great achievements have been made recently in neuroimaging techniques and computer technology for neuronavigation, from frameless, armless systems to robotic microscopes. Contained in the present volume are all the papers presented at the International Symposium on Computer-Assisted Neurosurgery and selected papers presented at the 6th Annual Meeting of the Japanese Society of Computers in Neurosurgery, which were held in Kobe, Japan, on January 24-26, 1997. This volume is a comprehensive description and review of current technical ad­ vancements in computer-assisted neurosurgery, with a special focus on advanced intraoperative neuroimaging, various neuronavigation system, robotic microscopes, and strategies for preoperative and intraoperative surgical planning using high-power workstations with three-dimensional software. We express our thanks to the contributors for their participation and cooperation, and to Springer-Verlag for personal and technical assistance in publishing this work. We sincerely hope that this volume will contribute to improving neurosurgical technology and outcomes.