From the 12th to the 15th September 1985 the International Symposium on Methods of Presurgical Evaluation of Epileptic Patients: Basics, Techniques, and Implications for Epileptology and Surgical Epilepsy Therapy was held in Zurich. This symposium was a consequence of the increasing recognition by Europeans, especially from Ger man-speaking countries, of a growing need for surgical therapy of epileptics. The main aim was to provide a venue for critical review and lively discussion of presurgical eval uation protocols, with special emphasis on the electrophysiological aspects, including in vasive techniques. To provide a necessary background, some basic aspects along with postsurgical results had to be dealt with by leading experts in the different fields of ex perimental and clinical epileptology and neurosurgery. It was intended to be an inter national but moderately scaled meeting. Finally, however, in addition to the European contingent, there were participants from Australia, Brazil, Canada, Israel, Japan, Korea, and the United States of America, including pioneers from the surgically active centers. This international discussion was surely facilitated by the close temporal relation ship to the International Congresses (XIIIth World Congress of Neurology and XVIth Epilepsy International Congress) which took place in Hamburg. And, probably most important, is the fact that the Zurich symposium was dedicated to Prof. Rudolf Hess and his lifelong devotion to epilepsy diagnosis and treatment in Switzerland, as out lined in the Honorary Address by his eminent colleague and personal friend, Prof. Henri Gastaut.