Like the Greeks who sailed with Jason in search of the Golden Fleece, the new Argonauts--foreign-born, technically skilled entrepreneurs who travel back and forth between Silicon Valley and their home countries--seek their fortune in distant lands by launching companies far from established centers of skill and technology. Their story illuminates profound transformations in the global economy.

Economic geographer AnnaLee Saxenian has followed this transformation, exploring one of its great paradoxes: how the "brain drain" has become "brain circulation," a powerful economic force for...