Substantiates the link between brain development and infant behavior and underlines the importance of early experiences and relationships in child development. The 4 interrelated domains of development -growth of the body, mind, person, and brain- highlight the central accomplishments of early childhood and underscore the obligations of caregivers to provide relationships that are warm and nurturing, experiences that stimulate the mind and the brain, and protection from physical danger and biological hazards. Parents and caregivers contribute to healthy brain development by talking, singing, reading to, and playing with a child; by securing appropriate immunizations, vision and auditory screenings, and health care; and by keeping stresses manageable. Society’s commitment to ensuring the healthy development of every child requires far more than hoping that market forces will make available high-quality, affordable care for young children. It requires equipping child-care providers with the knowledge, resources, and incentives necessary to provide young children the kind of focused, sensitive care that stimulates healthy psychological development. Attention to the social, emotional, and intellectual qualities that take shape early in life is one way a society can ameliorate future problems of violence, self-control, and social civility.