Chapter 5 discusses typical and atypical development among children, emphasizing the importance of monitoring developmental milestones from infancy to adolescence. It covers key theories of child development, including Erikson's psychosocial, Piaget's cognitive, Vygotsky's sociocultural, and Bandura's social learning theories, explaining how these frameworks contribute to understanding children's growth and learning processes. The chapter also delineates different domains of development—physical, social and emotional, language, and cognitive—along with the stages of development and the variability in children's growth trajectories.