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 volume for the length of time it has taken to produce a finished book. As you are all aware, the untimely death of Cheyne McCallum, who was to have been the sole editor of this volume, was very disruptive to both the book and myself. Following Cheyne's death I assumed the responsibility for completing the book as was his wish. I would like to thank you all for your patience and understanding. I would like to acknowledge my indebtedness to the Burden Neurological Institute in general and very specifically to Mrs. Chris Gough who has laboured extensively in the production of this volume.