Vascular biology has become one of the most exciting fields in the biomedical sciences. The development of molecular biology and of genetic approaches in the mouse embryo has large­ ly contributed to our current understanding of the biology of the vascular cell. Major advances have been achieved in the understanding of vascular development and in the role of the vas­ culature in various physiological or pathological processes. The aim of the present book is to provide the reader with a reference in which information can be looked-up quickly or to spark interest in a topic for later research. It should be valuable not only for scientists working actively in vascular biology or in related fields but also to clinicians because it will provide both with the necessary information about the physiopathological mechanisms encountered in their daily work. In addition, the book should also be of great help to teachers and to students in the life sciences. We did not want to organize this book in a textbook fashion. Instead, we chose to organize the book alphabetically, thus providing the reader with rapid access to information. However, we also wanted the various topics dealt with in enough depth for it not to be so condensed and short as in a lexicon. Thus, the book lies somewhere between the two.