This book reviews what is known about the Sonic Hedgehog pathway and the downstream Gli transcription factors during development. An introductory chapter reviews the pathway both in invertebrates and vertebrates. Subsequent chapters deal with the role of Shh during the development of specific organs and body systems in a variety of organisms including zebrafish, mouse and man. The book can be read in its entirety to provide readers with a comprehensive review of the importance of this signalling pathway for normal development and insights into on-going research in this field. Such an approach may be useful for under graduates or post-graduate students with an interest in development, cell signalling cascades or those specifically researching some aspect of Shh.