This useful study introduces readers to the tangled history of immigration policy in the United States. Such an introduction is badly needed: on the evidence of this book, much of U.S. immigration policy has been made by those who did not understand the consequences of the policies they struggled to enact. Before 1882, the country had no immigration policy: anyone who got here could stay here. But Americans already living here have always felt ambivalent toward new arrivals; while recognizing that immigrants provide cheap and willing labor, they have doubted the ability of various groups to assimilate. Benjamin Franklin worried about the Germans, and later generations worried about the Irish, the Italians, and the Jews. Historically, these fears have been expressed in terms of race; today, "culture" is the preferred term to distinguish the assimilable, useful immigrants from the purportedly dangerous ones. Daniels sees immigration policy moving in long waves. From 1882 to 1921, the doors were slowly closed. Immigration policy was tightest between the two world wars, but controls began to relax during Harry Truman's presidency. A second period of openness culminated in the amnesties of the 1980s. Now, with the percentage of foreign-born residents comparable to levels of a century ago, there may be further efforts at tightening ahead.