America offers opportunities for many immigrants to improve their earnings relative to what they could earn in their countries of origin, and research suggests that immigrants children tend to experience further economic gains. But the effect of immigrant workers on the earnings of low-skilled, native born workers may be significantly negative; some find that the recent influx of low-skilled, immigrant labor makes it more difficult for low-skilled native-born workers to gain higher wages. This review summarizes the highly charged debate over the positive and negative effects of immigration on economic mobility. (Review 7 of 11.)