David B. Grusky is Professor of Sociology and incoming Director of the Program on Inequality at Stanford University. His recent books include" Occupational Ghettos: The Worldwide Segregation of Women and Men "(Stanford 2004) and" Mobility and Inequality "(Stanford 2005). Ravi Kanbur is T.H. Lee Professor of World Affairs, International Professor of Applied Economics and Management, and Professor of Economics at Cornell University.