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