Integrated Principles of Zoology is a college text designed for an introductory course in zoology. This thirteenth edition, as with previous editions, describes the diversity of animal life and the fascinating adaptations that enable animals to inhabit nearly all conceivable ecological niches. Changes in this edition, more comprehensive than in revisions of the recent past, have touched virtually every aspect of the book, from thorough updating and incorporation of new findings to extensive revision of the art program. To provide fresh perspective to this edition we were fortunate to recruit three seasoned zoologists to revise the invertebrate chapters. They bring fresh viewpoints and approaches and the most current coverage from their areas of interest and research expertise.

We retain in this revision the basic organization of the twelfth edition and its distinctive features, especially emphasis on the principles of evolution and zoological science. Also retained are several pedagogical features that have made previous editions easily accessible to students: opening chapter dialogues drawn from the chapter's theme; chapter summaries and review questions to aid student comprehension and study; accurate and visually appealing illustrations; in-text derivations of generic names; chapter notes and essays that enhance the text by offering interesting sidelights to the narrative; and an extensive glossary providing pronunciation, derivation, and definition of terms used in the text.