This book is the product of a NATO Advanced Study Institute of the same name, held at the Anargyrios and Korgialenios School on the island of Spetsai, Greece, in September 1994. The institute considered the molecular mechanisms which generate the body plan during vertebrate embryogenesis. The main topics discussed included: commitment and imprinting during germ cell differentiation; hierarchies of inductive cell interactions; the molecular functioning of Spemann's organizer and formation of embryonic axes; the extracellular matrix and the cytoskeleton in relation to morphogenesis and cell...