Close relationships provide a fundamental context for human behavior and development and as such the study of close relationships has in recent years become a major theme in social psychology. This field produces rich and diverse research that can be daunting to access. Psychology of Close Relationships emphasizes original empirical investigations, as well as including conceptual papers that set the stage for relationship science or that build basic theories. Volume I: Theoretical Foundation - Why Relationships Matter focuses on basic theoretical arguments about the importance of relationships for human behavior and demonstrations of the consequences of relationships for health and well-being. Volume II: Attraction and Relationship Development covers the initiation and development of relationships by looking at classic processes such as similarity, proximity, familiarity, and attractiveness, as well as material on friendship formation, self-disclosure, and intimacy. Volume III: Relationship Cognition and Emotion includes articles on the emotional and cognitive processes that characterize relationships. Volume IV: Relationship Maintenance Processes delves into the processes relevant to maintaining and enhancing relationships and investigates interdependence theory, the leading approach to this topic. Volume V: Relationship Deterioration reviews research on the nature of relationship instability and deterioration, as well as what is known about their causes and consequences.