This book is based on two earlier works: Section IV is devoted to peripheral nerves, Aage R. Møller: Evoked Potentials in Intraop- and Chapter 12 covers the anatomy and physi- erative Monitoring published in 1988 by Will- ogy, whereas Chapter 13 discusses practical - iams and Wilkens; and more directly by Aage R pects of monitoring peripheral nerves. Møller: Intraoperative Neurophysiologic Moni- Section V discusses different ways that int- toring published in 1995 by Gordon and Breach operative electrophysiological recordings can under the imprint of Harwood academic publish- guide the surgeon in an operation. Chapter 14 ers. The present book represents an expansion discusses methods to identify motor and sensory and extensive rewriting of the 1995 book. In par- nerves and map the spinal cord and the floor of ticular, new chapters related to monitoring of the the fourth ventricle. Chapter 15 describes me- spinal motor system and deep brain stimulation ods that can guide the surgeon in an operation, (DBS) have been added. The anatomical and such as microvascular decompression operations physiological basis for these techniques are for hemifacial spasm and placement of el- described in detail as are the practical aspects of trodes for DBS and for making lesions in the such monitoring. Chapters on monitoring of sen- thalamus and basal ganglia. sory systems and monitoring in skull base sur- Section VI discusses practical aspects of - gery have been rewritten as has the chapter on traoperative monitoring.