at the University of Zurich more than 50 years ago. During the course of his remarkable career, he was instrumental in developing and refining many of the tools and techniques that even today remain indispensable gold standards in treatment. In 1999 the journal Neurosurgery honored him as Neurosurgery's Man of the Century 1950-1999." Professor Yasargil's lifetime achievements include: Integration of angiography and microsurgical techniques Development and application of innovative instrumentation, including the floating microscope, the self-retaining adjustable retractor, and ergonomic aneurysm clips and appliers Professor Yasargil's genius in developing microsurgical techniques for use in cerebrovascular neurosurgery has transformed the outcomes of patients with conditions that were previously inoperable. In this volume, you will witness the establishment of a major plateau in the evolution of modern neurosurgery.