This volume explores the various molecular pathways via which endothelial cells communicate among them as well as with other vascular cells (e.g., smooth muscle cells, leukocytes, platelets, fibroblasts, etc.) in order to transduce physiologic and pathologic signals. The most important pathologies discussed are: - pulmonary vascular diseases - thrombosis - hypertension (systemic and pulmonary) - inflammation - angiogenesis - cerebrovascular disease - transplantation - atherosclerosis. The largest fraction of time was devoted to the mechanisms and signals underlying these diseases.