The Atlas of Interpersonal Situations provides a systematic theoretical account for understanding the impact of situations on patterns of social interaction. Structured around descriptions of twenty-one of the most common situations that people encounter daily, this study presents the tools needed to understand how those situations influence interpersonal behavior. These descriptions are freestanding; each providing analysis, research examples, and everyday descriptions of the prototypical situation. The authors build upon interdependence theory, which stresses the manner in which outcomes are determined by the structure of interpersonal interaction. This analysis makes clear exactly what is "social" about "social psychology."