JORGE DURAND is professor in the Department for the Study of Social Movements at the University of Guadalajara and codirector of the Mexican Migration Project. DOUGLAS S. MASSEY is professor of sociology and public affairs at the Woodrow Wilson School of Public and International Affairs, Princeton University, and codirector of the Mexican Migration Project. CONTRIBUTORS: Patricia Arias, Maria Aysa, Marcela Cerrutti, Enrique Martinez Curiel, Katharine M. Donato, Jorge Durand, Nadia Y. Flores, Elizabeth Fussell, Ruben Hernandez-Leon, William A. Kandel, Douglas S. Massey, Margarita Mooney, Pia M. Orrenius, Emilio A. Parrado, Evelyn Patterson, Belinda I. Reyes, Fernando Riosmena, and Estela Rivero-Fuentes.