Bruce S. McEwen, Ph.D., obtained his Ph.D. in Cell Biology in 1964 from The Rockefeller University. He is a member of the US National Academy of Sciences, the National Academy of Medicine, and the American Academy of Arts and Sciences. He served as President of the Society for Neuroscience in 1997-98. As a neuroscientist and neuroendocrinologist, McEwen studies environmentally-regulated, variable gene expression in brain, mediated by circulating steroid hormones and endogenous neurotransmitters in relation to brain sexual differentiation and the actions of sex and stress hormones on the adult brain, in particular related to structural and functional plasticity via epigenetic mechanisms. His laboratory discovered adrenal steroid receptors in the hippocampus in 1968 that was the gateway for discovering effects of circulating hormones on cognitive function, mood regulation and other CNS functions. His laboratory combines molecular, anatomical, pharmacological, physiological and behavioral methodologies and relates their findings to human clinical information. His current research focuses on stress effects on amygdala and prefrontal cortex, as well as hippocampus, and his laboratory also investigates sex hormone effects and sex differences in these brain regions involved in cognitive function and mood regulation. He served on the MacArthur Foundation Research Network on Socioeconomic Status and Health, in which he has helped to reformulate concepts and measurements related to stress and stress hormones in the context of human societies, which led to the concept of “allostatic load and overload” that describes the wear and tear on the body and brain from chronic stress and related life style behaviors that lead to dysregulation of physiological stress pathways that are normally protective. He is also a member of the National Council on the Developing Child which focuses on biological embedding of early life experiences and promoting healthy brain development. He is the co-author of a book with science writer, Elizabeth Lasley, for a lay audience called “The End of Stress as We Know It”, published in 2002, and “The Hostage Brain” with science writer, the late Harold M. Schmeck, Jr., published in 1994, both of which are now available as eBooks.