Noting that social interaction theory has long been characterized by a plethora of divergent research studies in search of an organizing paradigm, and that a common failing of most social interaction research has been its focus on process or change in relationships, the first part of this paper specifies the major limiting, or boundary, conditions of social interaction. The second part of the paper discusses the six elements said to constitute the domain of social interaction: content, interpretation, emotions, transference, selection, and relationships. The third part of the paper explicates the major interrelationships among the elements within the domain of social interaction. This perspective is used in the last part of the paper to examine three middle range approaches to social interaction: relational communication, rules, and sequences. The paper concludes by suggesting that without an organizing paradigm, social interaction research will continue to be a field characterized by much activity, but also by a very halting and erratic development of conceptual understandings of the phenomenon which should be its focus of inquiry. (HOD)