HELEN FISHER, PhD, is Research Professor and member of the Center for Human Evolutionary Studies in the Department of Anthropology, Rutgers University. She has conducted extensive research on the evolution and future of human sex, love and marriage and gender differences in the brain and behavior.

She has written four books: Why Him? Why Her? How to Find and Keep Lasting Love; Why We Love: The Nature and Chemistry of Romantic Love; The First Sex: The Natural Talents of Women and How They are Changing the World; The Anatomy of Love: A Natural History of Mating, Marriage, and Why We Stray; The Sex Contract: The Evolution of Human Behavior