In this book, W. John Smith enlarges ethology's perspective on communication and takes it in new directions. Traditionally, ethological analysis has focused on the motivational states of displaying animals: What makes the bird sing, the cat lash its tail, the bee dance? The Behavior of Communicating emphasizes messages. It seeks to answer questions about the information shared by animals through their displays: What information is made available to a bird by its neighbor's song, to a cat by its opponent's gesture, to a bee by its hivemate's dancing? What information is extracted from sources contextual to these displays? How are the responses to displays adaptive for recipients and senders? What evolutionary processes and constraints underlie observed patterns of animal communication? Smith's approach is deeply rooted in the ethological tradition of naturalistic observations. Detailed analysis of observed displays and display repertoires illuminates the theoretical discussion that forms the core of the book. A taxonomy and interpretative analysis of messages made available through formalized display behavior are also developed. Smith shows that virtually all subhuman animal displays may be interpreted as transmitting messages about the communicator--not the environment--and, more specifically, that messages indicate the kinds of behavior the displaying animal may choose to perform. The most widespread behavioral messages are surprisingly general, even banal, in character; yet they make public information that is not readily available from other sources and that would otherwise be essentially private to the communicator. Taken along with information from sources contextual to the displays, the messages made available may permit responses that are markedly specific. By taking advantage of contextual specificity, a species expands the capacity of its display behavior to be functional in numerous and diverse circumstances. After developing the concept of messages and discussing their forms, the responses made to them, and the functions engendered, Smith turns to the evolution of display behavior--the ways in which acts become specialized for communication and the nature of the evolutionary constraints affecting the ultimate forms of displays. He revises the traditional ethological concept of displays, and in a final chapter develops the further concept of formalized interactions. Here he extends the discussion to formal patterns of behavior that, unlike displays, are beyond the capabilities of individual performers. Human nonverbal communication, which is considered from time to time throughout the book, provides the richest examples of communication flexibly structured at this level of complexity.