SAMUEL BOWLES, (PhD, Economics, Harvard University, 1965) is Research Professor at the Santa Fe Institute. He taught economics at Harvard from 1965 to 1973 and since then at the University of Massachusetts, where he is now emeritus professor, and at the University of Siena. His studies on cultural and genetic evolution have challenged the conventional economic assumption that people are motivated entirely by self-interest. Recent papers have also explored how organizations, communities and