This brief paper from Harvard University discusses the recent advances in some aspects of early child development which have important implications for policy and practice. (1) Even infants and young children are affected adversely when significant stresses threaten their family and caregiving environments. (2) Development is a highly interactive process, and life outcomes are not determined solely by genes. (3) While attachments to their parents are primary, young children can also benefit significantly from relationships with other responsive caregivers, both within and outside the family. (4) A great deal of brain architecture is shaped during the first three years after birth, but the window of opportunity for its development does not close on a child’s third birthday. (5) Severe neglect appears to be at least as great a threat to health and development as physical abuse—possibly even greater. (6) Young children who have been exposed to adversity or violence do not invariably develop stress-related disorders, or grow up to be violent adults. (7) Simply removing a child from a dangerous environment will not automatically reverse the negative impacts of that experience. (8) Resilience requires relationships, not rugged individualism.