Of the many themes that characterize U.S. history, immigration is one of the most constant and most pervasive. Since the first European and African immigrants began arriving in North America during the early seventeenth century, immigrants have steadily poured into what is now the United States. During the early twenty-first century, that flow has continued unabated - the major difference being that most immigrants now come from Latin America - especially Mexico and Central America - and Asia. Of the 281,421,056 residents of the nation counted by the U.S. Census in 2000, nearly 99 percent traced their ancestry to immigrants who arrived here within in the past four centuries. Moreover, even Native Americans - who make up the remainder - can trace their ancestry to immigrants who came thousands of years earlier. The United States is, indeed, a nation of immigrants. Because the United States is a nation of immigrants, it is obvious that most of the contributions to the building of the country have been made by immigrants and their descendants. Nevertheless, immigration has long been a subject of debate - and now more than ever, as Americans are increasingly feeling their security threatened by the constant flow of foreigners into the country. ""Immigration in U.S. History"" examines the many issues surrounding immigration - from the earliest settlement of British North America in the seventeenth century through the immediate aftermath of the of September 11, 2001, terrorist attacks of the twenty-first century. The two-volume set's 193 articles explore immigration from a wide variety of perspectives [note that many articles are counted under more than one heading: border control and law enforcement (20+ articles), court cases (9), demographics (47), discrimination (29), economic and labor issues (25), events (32), family issues (22), government and politics (13), illegal 17), language and education (15), laws and treaties (25), literature (3), nativism and racism (24), refugees (22), religion (21), sociological theories (14), and stereotypes (10). ""Immigration in U.S. History"" places special emphasis on the many ethnic communities that have provided American immigrants. Readers will find 17 articles treating African Americans; 56 articles about Asian immigrants, including articles specifically on Chinese, Filipino, Hmong, Korean, Japanese, Pacific Islander, South Asian, Southeast Asian, Tibetan, and Vietnamese immigrants; 25 articles on Latino and West Indian immigrants, including articles specifically on Cubans, Dominicans, Haitians, Jamaicans, and Mexicans; 10 articles on Middle Eastern immigrants, including articles specifically on Arabs, Iranians, and Israelis; 37 articles on European immigrants, including articles on German, Irish, Italian, Jewish, Polish, and Russian.