The diseases that fall under the generalized group of demyelinating diseases -Multiple Sclerosis, Leukodystrophyes, Encephalomyelitis-are the focus of worldwide concern. This volume contains papers presented by leading scientists who attended the NATO Advanced Research Workshop held at the Istituto Superiore di SanitA, Rome, March 1-4, 1993. This book is an update of the previous one published in 1987 of the research discussed at a similar meeting held in 1986. It was decided to hold this 2nd meeting since there has been great progress in the advances in understanding the myelinogenesis process in the last five years. The workshop gathered together scientists from many fields such as cellular and molecular biology, immunology, pathology, virology and of course clinical neurology. Stimulating ideas were exchanged in the hope that more knowledge of demyelinating diseases can lead to new theraupetic approaches. Although the workshop was on the whole similar to the previous one, this time there was more emphasis on experimental models and clinical aspects. In the former the use of animal and cellular models as tools for understanding the pathological mechanisms linked to human disease were discussed; in the latter the clinicians described the filtering down of basic research to clinical treatment The publication of this interdisciplinary exchange is to make known the results of the most recent research among the investigators from allover the world involved in these studies.