编者按：移民究竟是福还是祸，美国的学者和民众对此一直众说纷纭，莫衷一是，但没人可以否认移民对于美国社会的影响。同样由美国移民衍生出来的问题，我们也可以考虑一下中国的民工流动。

    Immigration to the United States of America has been a major source of population growth and cultural change throughout much of the American history even though the foreign born have never been more than 16% of the population since 1675. The economic, social and political aspects of immigration have caused controversy regarding race, ethnicity, religion, economic benefits, job growth, impact on upward social mobility, levels of criminality, moral values, and so on. As for 2006, the United States accepts more legal immigrants as permanent residents than the rest of the world combined. Overall, there are an estimated 30 million immigrants in the country - of which about 8.5 million are here illegally.

    虽然从1675年以来 ......