Book excerpt: A group of special interest to mammalogists, taxonomists, and systemicists, ungulates have proven difficult to classify. This comprehensive review of the taxonomic relationships of artiodactyls and perissodactyls brings forth new evidence in order to propose a theory of ungulate taxonomy. With this straightforward volume, Colin Groves and the late Peter Grubb cut through previous assumptions to define ungulate genera, species, and subspecies. The species-by-species accounts incorporate new molecular, cytogenetic, and morphological data, as well as the authors’ own observations and measurements. The authors include references and supporting arguments for new classifications. A starting point for further research, this book is sure to be discussed and hotly debated in the mammalogical community. A well-reasoned synthesis, Ungulate Taxonomy will be a defining volume for years to come.