Guests and Aliens presents a comprehensive analysis of worldwide immigration by one of the worlds leading experts on globalization. Putting the current crisis of immigration into a historical context for the first time Sassen suggests that the American experience represents only one phase in a history of global border crossing. She describes the mass migrations of Italians and Eastern European Jews during the nineteenth and early twentieth centuries and the international dislocationsparticularly after the end of World War IIthat have engendered the refugee concept. Using these examples Sassen explores the causes of immigration that have resulted in nations welcoming incomers as guests or disparaging them as aliens and outlines an enlightened approach Publishers Weekly to improving US and European immigration policies.