NORMAN E. ROSENTHAL, M.D., is a professor of psychiatry and researcher who was the first psychiatrist to describe and diagnose Seasonal Affective Disorder (SAD). A New York Times bestselling author, his books include Transcendence, The Gift of Adversity, and Super Mind: How to Boost Performance and Live a Richer and Happier Life Through Transcendental Meditation. www.NormanRosenthal.com.