Written by the renowned Swiss naturalist Louis Agassiz, this book presents a detailed analysis of the principles underlying the classification of animals. It proposes a new system of classification based on the study of embryology and anatomy, and offers insights into the relationships between different groups of animals. This classic work of natural history is still widely read and admired by scholars and students of biology. This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work is in the "public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.

Embracing more than 5,000 genera, distributed in 425 families and 46 orders, Malcolm C. McKenna and Susan K. Bell's Classification of Mammals is the most comprehensive work to date on the systematics, relationships, and occurrences of all mammal taxa, living and extinct, down through the rank of genus. Since George Gaylord Simpson's 1945 classification, the paleontological record has been recalibrated, and the intervening years have seen much debate and progress concerning the theoretical underpinnings of systematization. McKenna inherited the project from Simpson and, with Bell, has constructed a completely updated hierarchical system that reflects the genealogy of Mammalia.