This volume argues that the commitment to justice is a fundamental motive and that, although it is typically portrayed as serving self-interest, it sometimes takes priority over self-interest. To make this case, the authors discuss the way justice emerges as a personal contract in children's development; review a wide range of research studying the influences of the justice motive on evaluative, emotional and behavioral responses; and detail common experiences that illustrate the impact of the justice motive. Through an extensive critique of the research on which some alternative models of justice are based, the authors present a model that describes the ways in which motives of justice and self-interest are integrated in people's lives. They close with a discussion of some positive and negative consequences of the commitment to justice.