"In preparing this work for the public, the writer was chiefly influenced by a desire to collect the truths of Zoology within a small compass, and to render them more intelligible, by a systematical arrangement. He is not aware that there exists any work in the English language, in which the subject, in its different bearings, has been illustrated in a philosophical manner, or to which a student of Zoology could be referred, as a suitable introduction to the science. There are not wanting, it is true, many disquisitions of great value, on particular departments of the physiology and classification of Animals. But the writings of these naturalists, and others which have been noticed in the body of the work, are not only rare, but expensive; so that the task of investigating the facts which have been established, or the theories which have been proposed, can scarcely, in ordinary circumstances, be entered upon. The want, indeed, of such an introduction to the study of the Animal Kingdom, as should serve as an index to the doctrines on which the classification is founded, has frequently been the subject of regret, and may probably be considered as the origin of that indifference to the science which is but too apparent in this country. This work aims to provide such an introduction by providing a view of the structure, functions, and classification of animals"--Preface.