The study of animal communication requires a broader set of perspectives than nearly any other topic in biology. Relevant disciplines include physics, chemistry, neurobiology, cognitive science, evolutionary biology, behavioral ecology, and economics. Principles of Animal Communication integrates all of these approaches in its treatment of animal signal evolution. The taxonomic scope is kept broad, and all sensory modalities are discussed. The text is aimed at upper-level undergraduate or beginning graduate students. Quantitative approaches are emphasized but kept to the level of simple algebra, and the relevance of all results and analyses is explained verbally. Many unresolved issues for future research are identified. Topics begin with the physics and physiology of signal production, propagation, and reception, turn to the economics of cooperating communicators, and end with the complications arising when sender and receiver do not have identical interests during communication. A variety of signal analysis and evolutionary methods are explained and demonstrated with examples. Principles of Animal Communication can be used as the basis for a general introduction to animal communication studies or, by focusing on specific sections, for more specialized and advanced courses. Abundantly illustrated and cross-referenced, the text features an extensive bibliography and suggestions for further reading. In addition, chapter-end summaries underscore critical points raised in the text, while boxes throughout provide additional explanations or outline advanced approaches.