Prosocial behavior - broadly defined as voluntary action intended to help or benefit another - has been associated with positive outcomes across the lifespan. Children with a more prosocial orientation are better liked and trusted by their peers, have a higher status in peer groups, are betterat maintaining friendships, demonstrate better self regulation, empathy, and social cognitive skills, and excel in academics. Researchers have shown that prosocial behaviors correlate to lower rates of school suspension and drop-out, teen pregnancy, substance use, aggression, and delinquency. Thesepositive effects speak to the value of prosocial behavior during formative years.Prosocial Development examines a variety of biological, socialization, and contextual influences on prosocial development from infancy through early adulthood. While the definition of prosocial behavior may seem straightforward, recent research has highlighted its multifaceted nature. This volumespecifically focuses on the multidimensionality of prosocial development, examining different contexts, motivations, types, and targets of prosocial behavior that are differentially predicted by socialization and dispositional characteristics. Skillfully edited by Drs. Padilla-Walker and Carlo, eachchapter in this volume highlights some aspect of multidimensionality in regard to prosocial behavior and meaningful avenues for future research. This volume will be an important tool for scholars, researchers, and practitioners who are interested in prosocial, moral, and positive youth development.The organization and focus of this volume are also well-suited for use as a text for graduate courses in moral development, child and adolescent development, social psychology, sociology, anthropology, and family studies.