Currently, the cellular and molecular mechanisms governing the development and regulation of the vasculature are studied in tensely and the field is rapidly progressing. Recently, novel growth factors and growth factor receptors specifically acting on endothelial cells have been discovered. Through these factors, communication networks are established between endothelial cells, the basement membrane and the pericytes; this interplay is critical for the regulated development and maintenance of the vasculature. The awareness that deregulated angiogenesis con tributes to the progression of a number of diseases, such as cancer and inflammatory diseases, has clearly spurred the field to move forward. The focus of this book is on two important classes of endothelial cell specific growth factors, the vascular endothelial growth factor (VEGF) family, and the angiopoietins, and on their mechanisms of action. The reader will find up-to-date, fo cused reviews, which give the current picture, and indicate future directions. I would like to honor Dr. Judah Folkman for his important contributions to the establishment of the field and thank him for his support. Lena Claesson-Welsh List of Contents N. FERRARA Vascular Endothelial Growth Factor: Molecular and Biological Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . M. G. PERSICO, V. VINCENTI and T. DIPALMA Structure, Expression and Receptor-Binding Properties of Placenta Growth Factor (PIGF) . . . . . . . . . . . . . . . . . 31 U. ERIKSSON and K. ALiTALO Structure, Expression and Receptor-Binding Properties of Novel Vascular Endothelial Growth Factors. . . . . . . . . 41 M. SHIBUYA, N. ITo and L. CLAESSON-WELSH Structure and Function of Vascular Endothelial Growth Factor Receptor-I and -2 . . . . . . . . . . . . . .. . . . 59 J. TAIPALE, T. MAKINEN, E. ARIGHI, E.