Introduction: The problem of determinants and mechanisms of child development : the structure and content of the book -- Vygotsky's approach to child development -- The neo-Vygotskian elaboration of Vygotsky's approach to child development -- First year of life : emotional interactions with caregivers as the leading activity of infants -- Second and third years of life : object-centered joint activity with adults as the leading activity of toddlers -- Three to six-year-olds : sociodramatic play as the leading activity during the period of early childhood -- The period of middle childhood : learning at school as children's leading activity -- The period of adolescence : interactions with peers as the leading activity of adolescents -- The neo-Vygotskian approach to child development : accomplishments and shortcomings.