This volume brings together for the first time the papers which have shaped and defined the field of interpersonal development. It celebrates the maturation of the subject by bringing together the best work by scholars who have been instrumental in furthering the field. The twenty-seven essays describe developmental changes in interactions within specific close relationships, covering parent-child relationships, friendships and peer relationships, romantic and spousal relationships, and sibling relationships. They also detail characteristics of specific relationships and interconnections among these key features, as well as tying close relationships to individual outcomes. The essays are accompanied by an introduction which offers a brief history of the field, a review of relationship definitions and a detailed preview of the articles.