This paper unifies two strands of theoretical method in sociology. On the one hand, the structuralist or network program of research involves the fundamental rule that basic data and analytic procedures of sociology must focus on social relations. This leads to theories about structural stabililty or change, for example, although the network approach generally has been stronger on technique than on explanatory theory. An interest in theoretical explanation is the basis of the second theoretical method, which is drawn from the expectation states theoretical research program: namely, the idea of a dynamic co-causal process involving an unobservable relational construct termed an expectation state and an observable form of social behavior. The paper outlines the basic ideas of each of these two theoretical methods. It then proposes a new theoretical method which synthesizes the two and whose function is to provide a procedure for constructing explanatory models of social structural stability and change. This new method is termed "E-state structuralism." An extended example is provided of how the method is used to construct a theory, first presenting the theory in axiomatic form and then empirically testing it. The subject matter of the theory is the over-time transformation in the structure of dominance relations among a small group of animals. The paper concludes with a review of how the generic method was exemplified in the particular theory.