This Q&A interview with Center Director Jack P. Shonkoff [1]focuses on the issue of toxic stress. Toxic stress [2] refers to what occurs when the body’s stress response system is activated for long periods of time—by such triggers as recurrent abuse, chronic neglect or prolonged exposure to violence—without being able to calm down and return to baseline. As the brain is developing during a child’s early years, it is very sensitive to stress hormones, Dr. Shonkoff explains, and their chronic elevation can damage developing brain circuitry, with lifelong consequences for the individual and for society. The interview was conducted by Karen Weintraub.