Abstract The most comprehensive summary available on the stratigraphic occurrence, geographic distribution, phylogeny, and taxonomy of Early Permian colonial rugose corals that occupied the Cordilleran–Arctic–Uralian (CAU) Realm, along the northwestern and western marine shelves and accreted terranes of the ancient supercontinent Pangaea. It is based on all previous studies by other coral specialists, a thorough review of all published data, and on information from a very large number of new collections from new areas. This book contains a new classification and phylogenetic scheme, based on critical restudy of the entire coral fauna at all taxonomic levels