Introduction: studying human development -- Theories of development -- Genetics -- Prenatal development and birth -- Physical development in the first two years -- Cognitive development in the first two years -- Psychosocial development in the first two years -- Physical development in early childhood -- Cognitive development in early childhood -- Psychosocial development in early childhood - Physical development in middle childhood -- Cognitive development in middle childhood -- Psychosocial development in middle childhood -- Physical development in adolescence -- Cognitive development in adolescence -- Psychosocial development in adolescence