Martin E.P. Seligman, Ph.D., works on positive psychology, learned helplessness, depression, and on optimism and pessimism. He is currently Zellerbach Family Professor of Psychology and Director of the Positive Psychology Center at the University of Pennsylvania. He is well known in academic and clinical circles and is a best-selling author.His bibliography includes twenty books and 200 articles on motivation and personality. Among his better-known works are Learned Optimism (Knopf, 1991), What You Can Change & What You Can't (Knopf, 1993), The Optimistic Child (Houghton Mifflin, 1995), Helplessness (Freeman, 1975, 1993) and Abnormal Psychology (Norton, 1982, 1988, 1995, with David Rosenhan.His most recent book is the best-selling, Authentic Happiness (Free Press, 2002). He is the recipient of two Distinguished Scientific Contribution awards from the American Psychological Association, the Laurel Award of the American Association for Applied Psychology and Prevention, and the Lifetime Achievement Award of the Society for Research in Psychopathology. He holds an honorary Ph.D. from Uppsala, Sweden and Doctor of Humane Letters from the Massachusetts School of Professional Psychology.