This monograph first reviews a theory of individual communication behavior and points out the similarities between that theory and the observed activities of public relations practitioners. It then reviews the literature of formal organizations to extend the theory to more complex systems. Next, it operationalizes this expanded theory and reports the results of a field study of public relations practitioners designed to test the hypotheses derived from the theory. Finally, it discusses the implications of the theory and this research for the teaching and practice of public relations. (Author)