Introduction, Part 1 Educational intervention and teaching 1 Educational implementation and teaching: 'School knowledge' and psychological theory 2 Piaget and Vygotsky: A necessary marriage for effective educational intervention 3 Psychological theory that 'works' in the classroom Part 2 Social collaboration and learning 4 Psychological development as a social process 5 Revisiting young Jean Piaget in Neuchatel among his partners in learning 6 Piaget, Vygotsky and the social dimension Part 3 Cognitive skills and domain specificity 7 Piaget, mathematics and Vygotsky 8 Socializing intelligence 9 Expertise and cognitive development: Seeking a connection Part 4 Measurement of development 10 Measuring development: Examples from Piaget's theory 11 Capturing dynamic structuralism in the laboratory 12 Why measure development? Part 5 Development of modal understanding 13 Children's understanding of permission and obligation 14 Necessary knowledge and its assessment in intellectual development 15 Modality and modal reasoning