This book discusses the economics of immigration, analyzing immigrants' skills, national origins, welfare use, economic mobility, and impact on the labor market and using new data to trace current trends in ethnic segregation. Twelve chapters examine (1) "Reframing the Immigration Debate"; (2) "The Skills of Immigrants"; (3) "National Origin"; (4) "The Labor Market Impact of Immigration"; (5) "The Economic Benefits from Immigration"; (6) "Immigration and the Welfare State"; (7) "Social Mobility across Generations"; (8) "Ethnic Capital"; (9) "Ethnic Ghettos"; (10) "The Goals of Immigration Policy"; (11) "A Proposal for an Immigration Policy"; and (12) "Conclusion." The book concludes that the country would benefit from a more skilled, and slightly smaller, immigrant flow. It explains that the economic impact of immigration is a distributional one, with immigration shifting wealth away from those who compete with immigrants' skills and abilities and toward those who employ or use those immigrant resources. While those who lose from immigration tend to be quite diffused, the winners are much more concentrated and better organized, with many immigrants employed in a few industries and the employers in those industries gaining substantially. There are dangers ahead because of powerful interest groups that gain substantially from current immigration policy. (SM)