Sonic Hedgehog Signalling in Dorsal Midline and Neural Development -- Role of Hedgehog and Gli Signalling in Telencephalic Development -- Role of Shh and Gli Signalling in Oligodendroglial Development -- The Role of Sonic Hedgehog Signalling in Craniofacial Development -- Multiple Roles for Hedgehog Signalling in Zebrafish Eye Development -- Sonic Hedgehog Signalling during Tooth Morphogenesis -- Limb Pattern Formation -- Sonic Hedgehog Signalling in the Developing and Regenerating Fins of Zebrafish -- Hedgehog Signalling in T Lymphocyte Development -- Hedgehog Signalling in Prostate Morphogenesis -- Sonic Hedgehog Signalling in Visceral Organ Development -- Shh/Gli Signalling during Murine Lung Development -- New Perspectives in Shh Signalling?. he hedgehog signalling pathway is highly conserved and seen in organisms ranging from Drosophila to humans. This pathway is Tcritical in determining cell fate decisions in a variety of different cell types. There are several vertebrate analogues of the Drosophila hedgehog protein of which the most widely studied is Sonic hedgehog (Shh). Shh signalling classically involves the Gli family of zinc-fmger transcription factors. The Shh signalling pathway is well characterised in the development of a number of vertebrate organ systems. It could indeed be argued that the Shh and Gli signalling may well be involved at some stage in the development of all the major organ systems in vertebrates. This volume represents a concerted drive to bring together *state of the art' reviews by leading experts in the field of Shh and Gli signalling in development from all over the world. The chapters span vertebrate organisms from zebrafish to humans and cover development of the multiple organ systems in which the Shh signalling pathway is crucial for normal development. There are chapters on the development of the central nervous system, skeletal structures, visceral organs, prostate, lung, immune system and the structures of the human face. The authors themselves span three major continents and multiple nationalities which admirably illustrates the worldwide nature of the science.