This book is a unique text that illustrates and describes all the nominal genera of Cretaceous ammonites and their Jurassic progenitors on the basis of their type species.

There is no judgement as to validity, and the authors leaves it to the reader to subjectively recognize or synonymize those taxa as they see fit, based on the premises and philosophies to which they ascribe. The author argues that the taxonomy offered by the Treatise, the fundamental reference work, is no longer appropriate and genera need to be redefined according to testable hypotheses. The purpose of this book, therefore, is redescribe the type species of every nominal genus and to use these to construct a new phylogenetic classification not hampered by preconceived opinion. It emphasizes the importance of "trifling characters" for classification, and that taxonomic rank is not optional but is predetermined by evolutionary position. A new higher classification is introduced for the group using the higher taxa proposed for the phylogenetic classification of the Bivalvia. Hypothesized relationships are depicted by the use of cladograms, recognizing these portray only affiliations among the sample and not necessarily close taxonomic bond.

This book will be of great interest to palaeontologists, geologists, stratigraphers, biogeographers and interested students of geology, and paleology. It will also make a good addition to universities, museums, and public libraries.