Lionel Tiger is the Charles Darwin Professor of Anthropology at Rutgers University. His title reflects his pioneering role in introducing biosocial data into the social sciences. Since the mid-1960's he has been deeply involved in bridging the gap between the natural and social sciences. He has asserted that the words used appear to imply that human social behavior is somehow not natural. But of course it is. Exploring how and why is Tiger's central adventure. As a teacher, writer of books and articles which have been widely published and translated and as co-Research Director of the Harry Frank Guggenheim Foundation, he has been an influential figure in broadening our knowledge about why we do what we do.