This volume is based on the proceedings of a NATO Advanced Research Workshop on Slow Potential Changes in the Human Brain that was held at II Ciocco, Tuscany, Italy over the period 13-16th May, 1990. The Workshop Director was Dr. W. C. McCallum of the Burden Neurological Institute, Bristol, England. The meeting was superbly organised and proved to be both stimulating and productive. On behalf of everyone who attended the meeting, I would like to II Ciocco for express my appreciation to NATO for the provision of funding and to providing such a marvellous conference venue. I must apologise to everyone who has contributed to this