This research focuses on social networks, which are designed to study the relationships among individuals or other social entities. Applications of the research are numerous, and include clinical and community psychology, social psychology, organizational studies, and anthropology. A four year program of research will be undertaken by the investigator and his collaborators to study social network methodology and applications. Much of this research makes use of a new family of statistical models for social networks, based on spatial interaction models. There are five major areas of research proposed: (1) Multivariate generalizations of this new family of models; (2) Additional work on the statistical properties of the family; (3). Continued work on a merger of algebraic and statistical models; (4) New approaches to the analysis of longitudinal networks; and (5) New applications of the statistical methodology, particularly to cognitive social structures and epidemics. This research program will generate and improve tools for a more rigorous empirical analysis of social and behavioral research, and should provide statistical results of interest to methodologists.