In this volume leading developmentalists address the question of how children's thinking develops in context by drawing on the theories of Vygotsky, Gibson, and Piaget. Analyses of the ecology and the dynamics of behavior have become popular, emphasizing the particulars of people acting in specific environments and the many complex factors of human body and mind that contribute to action and thought. This volume brings together many of the current efforts to deal with development in this richly ecological, dynamic way. The research reported demonstrates that recent years have produced major shifts in approach. Activities are studied as they naturally occur in everyday contexts. Children's active construction of the world around them is treated as fundamentally social in nature, occurring in families, with peers, and in cultures. Behavior is studied not as something disembodied but within a rich matrix of body, emotion, belief, value, and physical world. Behavior is analyzed as changing dynamically, not only over seconds and minutes, but over hours, days, and years.