This book is the first attempt to collate all the information known to date on the small vertebrates, e.g. mammals, crocodiles, turtles, lizards, frogs, salamanders, etc., and features contributions by experts with international reputations in their fields. There are chapters on the taxonomy and phylogeny of the key vertebrate groups followed by a section dealing with the most significant fossiliferous assemblages worldwide. The final section looks at how faunal turnover at this time is measured and examines the possibility of mass extinctions.