This book is intended for teachers who work with young children, students of developmental and educational psychology, parents, as well as staff with administrative functions related to curricula. It shows how teachers can use Piaget's theory in the classroom in a global educational program through group games. Collective games stimulate children's development, and the authors' objective is to show what children can learn with these games and how teachers can intervene to maximize children's learning. They try to recognize the educational value of games and the extent to which children learn much more by participating in collective games than with many traditional lessons and exercises. On the other hand, they recover, contrary to the position of some educational psychologists, the role highlighted by Piaget in some of his works on the importance of social interaction with peers: «Piaget affirmed that without social interaction with other children, children Children cannot build their logic or their social and moral values.