This monograph contains the proceedings from the Advanced Study Institute on Vascular Endothelium: Physiological Basis of Clinical Problems which took place in Corfu, Greece in June 1990. The meeting consisted of twenty-eight lectures, most of them adapted as full length papers in this volume, as well as numerous short oral and poster communications which are abstracted and also included in alphabetical order (pages 239-302). There were ninety-six participants from ten NATO and four other European countries. The meeting was the second in as many years dealing with a specific subject in Endothelial Cell biology. Following the 1988 discussion on Receptors and Transduction Mechanisms , the present ASI recognized and tried to deal with the increasing overlap in interest between basic scientists studying endothelial cell functions and clinicians facing problems of known or suspected endothelial pathological involvement. As with any similar effort, we opted to be selective, rather than fail by trying to be inclusive, in the subjects covered. We chose to discuss diseases, such as atherosclerosis, sepsis, ARDS and stroke, based on their relevance to endothelial cell function and urgent need for new insights into their pathogenesis and treatment. Similarly, we examined endothelial cell functions by considering their relevance to disease and their potential for elucidating important pathologies. Obviously, some areas were covered superficially or not at all; this should not distract from their importance, but rather reflect on the constraints of time and -not at all negligibly -the bias of the organizing committee.