PIP: This article, which is in two parts, examines aspects of current U.S. concerns about immigration. The first part, by Nicole Morgan, summarizes some of the recent work by David M. Kennedy and Georges J. Borjas on the benefits and costs of immigration. The second part, by Remy Oudghiri, examines the growing concern among some whites in California who fear the consequences of becoming the minority rather than the majority population in the state. The importance of taking economic and social factors into account in the resolution of problems associated with immigration is stressed.