The exquisitely preserved, diverse and abundant fossil assemblages yielded by the ‘echinoderm meadows’ of the Tafilalt region of the eastern Anti-Atlas represent a new Konservat-Lagerstätte, one of the few exceptionally preserved Late Ordovician open-marine faunas found globally, giving us an insight into the radiation of life during the later phases of the Great Ordovician Biodiversification Event (GOBE) in high-latitude peri-Gondwana. The GOBE resulted in an unprecedented increase in the diversity of families, classes and orders, at the fastest rate of the entire Phanerozoic and represents one of the most significant events in the evolution of the marine biosphere, preceding the end-Ordovician mass extinction. Nine different phyla and several soft-bodied problematica are represented in the Tafilalt, including several notable echinoderm Lagerstätten. This volume is the culmination of over 20 years of research by several international teams and integrates a series of contributions that look at diverse aspects of the biota, including the stratigraphic distribution of the faunas, depositional environments, systematic palaeontology, preservation, palaeobiogeography and the nature and impact of the international fossil trade on these exceptionally preserved fossil faunas.