Structural analysis of social behavior (SASB) is a model that can be used to assess interpersonal and intrapsychic interactions in terms of three underlying dimensions: (a) focus (other, self, introject), (b) affiliation-hostility (love-hate), and (c) interdependence-independence (enmeshment-differentiation). Assessment of individuals or groups in terms of these dimensions can be made by self-ratings on the SASB Intrex questionnaires, ratings by others using the same questionnaires, or by objective observer ratings. Data generated by questionnaires or formal codes yield identical summary parameters, making it possible to compare directly objective observer assessments with self-ratings, if desired. The goal of this chapter is to help the reader understand the structure of SASB, become aware of how it has been used in studying interpersonal and intrapsychic events, assess its validity, assess the substance and relevance of criticisms, and consider future possibilities.