In this section, we explore the intricate nature of human development. Development is viewed as a continuous process that begins at conception and culminates in old age, involving a series of predictable and progressive changes. The Life-Span Perspective on Development is introduced, emphasizing that development is lifelong, multidirectional, and influenced by various interrelated processes, including biological maturation, cognitive growth, and socio-emotional interactions. Key concepts such as growth, maturation, and the influence of environment on development are discussed, along with the various stages humans pass through during their lifespan. The section highlights the uniqueness of each individual’s developmental experience, shaped by their genetic inheritance and social contexts.