Book excerpt: Inspired by the research and theory of Robert Freed Bales (Professor Emeritus of Sociology at Harvard University), this collection of research and applications using SYMLOG, a system for the multi-level observation of groups, provides the most recent examples of analyzing aspects of social interaction systems. The collection shows the relationship of SYMLOG to other theoretical models, gives examples of international research, includes applications in health, education, religion, and policy analysis, and illustrates problems and solutions regarding the validity and reliability of the method. The editors provide the widest selection of articles on SYMLOG, covering theory, research, and applications in organizational development and other fields.