This new edition of Animal Behavior has been completely rewritten with coverage of much recent work in animal behavior, resulting in a thoroughly up-to-date text. Notable is the inclusion, for the first time, of discussion questions embedded in the text itself, rather than appended to the end of each chapter. This format is designed to encourage students to reflect on the material they have just digested while also making it easier for instructors to promote a problem-solving approach to the subject in their classes. Another key organizational improvement is the consolidation of what had been two separate chapters on the genetic and environmental influences on development. By combining this material, the new Chapter 3 makes a stronger, more tightly argued case for the view that development is a truly interactive process codependent on both genetic and environmental factors. <P>Like previous editions, the book shows how evolutionary biologists analyze all aspects of behavior. It is distinguished by its balanced treatment of both the underlying mechanisms and evolutionary causes of behavior, and stresses the utility of evolutionary theory in unifying the different behavioral disciplines. Important concepts are explained by reference to key illustrative studies; examples are drawn evenly from studies of invertebrates and vertebrates, and are supported by nearly 1,300 reference citations. The writing style is clear and engaging: beginning students have no difficulty following the material, despite the strong conceptual orientation of the text. <P>Throughout, the author keeps the essence of the scientific enterprise clearly in front of the student reader. The text stresses the role of theory and hypothesis-testing in doing science. The book also emphasizes the tentative nature of scientific conclusions, and it identifies controversial and unresolved issues.