The first volume dedicated solely to the Ammonoidea was published in 1957. It covered not only the different groups of ammonoid cephalopods, but included also chapters on morphology, evolution, paleoecology, and geographic distribution. Between 1954 and 1965, more than 100 new genera were established worldwide. Therefore, in February 1967, plans to revise Treatise Part L were discussed.
In 2004, W. M. Furnish, B. F. Glenister, J. Kullmann, and Zhou Zuren decided to put together the Carboniferous and Permian parts and asked the Editorial Office at the Paleontological Institute of the University of Kansas in Lawrence to accept both unified parts for the Treatise series of revised parts. The uninterrupted evolutionary lines between the Carboniferous and Permian made possible a similar treatment of taxonomic descriptions and literature.
The present volume reflects a considerable amount of paleontological research of the last century. In 1988 Zhou Zuren joined the Iowa group of if scientists specializing in Permian ammonoids. The new interpretation of the sutural pattern of the early stages of coiling, EALUI [German] and VLU:ID [Russian] instead of ELU2:U1:I or VUU1:ID in Prolecanitida may be of great consequence for the evaluation of phylogeny. It has led to the idea of a much closer affinity of the orders Prolecanitida and Goniatitida. Many representatives of aberrant endemics, mainly the pseudohaloritaceans, kufengoceratins, and paragastrioceratids reported from South China, suggest a widespread ecological differentiation among Permian ammonoids. The combination of these special faunas vith special environments has led to a new understanding of ammonoid provincialism. Dimorphism is known to be a common phenomenon in the Permian period. A regressive evolution pattern existed in some late Paleozoic ammonoid families: a kind of terminal paedomorphosis has been verified in many genera and their family groups. As is explained in one of the old Treatise prefaces: the making of a reasonably complete inventory of present knowledge may be expected to yield needed foundation for future research, and it is hoped that the Treatise will serve this end.