The topic "Cerebrovascular Transport Mechanisms" was chosen by the General Couneil of the International Society of Neuropathology as one of the four main symposia at the IX International Congress of Neuropathology, September 1982 in Vienna. The chairmen of the symposium were asked to structure a program which would cover the reeent devel- opments in this field and which could serve as a background for free communications, relevant to this topic, submitted by the participants of the Congress. Cerebrovascular transport mechanisms refleet the main function of the blood-brain barrier in providing optimaI, homeostatically regulated, biochemical environment for the brain. It is obvious that disturbanees of this function may play a significant role in patho- physiology of various brain disorders. Since the elucidation of the complex blood-brain barrier phenomenon, consisting of various "barrier systems", necessarily requires applica- tion of multidisciplinary approaches, the program of this symposium was structured by evaluation of ultrastructural, cytochemical, physiological, biochemical, pathophysiological and therapeutic aspects of the blood-brain barrier by invited, recognized experts in respec- tive areas. As aresult, this volume of the proceedings of the symposium attempts to summarize much of today's knowledge on cerebrovascular transport mechanisms in health and disease, and is supplemented by the abstracts of free communications dealing with the most reeent research in this field. We hope that this volume wil1 serve both as an introduction and a reference book, and that it wil1 stimulate further research.