Developmental studies in interpersonal communication have focused on first-order development—relational development within a given matrix of rules. Neglected has been the interpersonal communication that results in second-order development—the creation of a new interpersonal system. A rationale, a model, and procedures for the study of second-order development are presented. A case is analyzed, and several conclusions are proposed. Second-order development (1) follows a predictable pattern, (2) it is marked by personal struggle, (3) its outcomes are oblique to its happening, and (4) it involves risk. Future research is directed toward the effects on second-order development of certain kinds of episodes and their sequential order and toward the use of the procedures demonstrated in analyzing the development of long-standing relationships.