Martin E. P. Seligman is the most influential psychologist in the world (Academic Influence) and a professor at the University of Pennsylvania, where he directs the Positive Psychology Center. A former president of the American Psychological Association, he earned his BA in philosophy from Princeton and his PhD in psychology from Penn, and holds ten honorary doctorates. His research--from learned helplessness to learned optimism to prospection--has reshaped how science understands human well-being. He is the author of more than thirty books, including Flourish, Authentic Happiness, The Hope Circuit, and Tomorrowmind.