This chapter presents an overview of normative development during the preschool years, a period marked by rapid advances in multiple domains. It begins by highlighting the key characteristics of children aged 3 to 6 years, followed by a structured discussion of developmental progress in the physical, motor, language, cognitive, social, and emotional domains. A central focus of the chapter is the role of Play in early childhood development—not merely as recreation but as a powerful medium for learning, socialization, and emotional expression. Drawing on developmental theories and empirical research, the chapter illustrates how play supports key competencies and reinforces developmental milestones. The chapter concludes with a presentation of age-appropriate developmental milestones during this period, helping parents, educators, and practitioners recognize typical patterns of growth and identify early signs of developmental delays.