Williamson (Roughnecking It, 1982, etc.) examines the intertwined economic and moral issues presented by the immigration debate. The author, formerly an editor of National Review, challenges what he calls the ``myth'' that immigration was always a blessing for America. He concedes that the vast numbers of immigrants from Britain, Germany, and Ireland who came here in the 19th century, despite sometimes strong opposition, were needed to settle the land. These immigrants gradually absorbed American culture and were in turn absorbed into American society. Williamson sees the massive immigration from 1870 to the 1920s as the start of great and disruptive changes, citing gradual but persistent negative effects on national identity, social and political order, population growth, and the environment. While earlier immigrants may have had a disruptive effect on America, Williamson sees the massive numbers of modern immigrants, both legal and illegal, from Asia, Latin America, the Caribbean, Africa, and eastern Europe, and their embrace of the concept of multiculturalism, as challenging the very idea of a special American identity. He argues that the newcomers have produced levels of cultural, ethnic, and social diversity that have had the effect of loosening the old American commitment to a distinctive, homogenous identity. Rather than being transformed by American culture, the author argues, these immigrants have tried to remake it, pressing for a larger and ever-more intrusive government, thus undermining traditional American concepts of personal liberty and self-reliance, and arguing against any cohesive national culture. Williamson points to such developments as the tensions between Cuban immigrants and poorer African- Americans in Miami as demonstrating that immigration is also generating new, and potentiallly violent, economic conflicts in American society. The book, largely polemical, would have benefitted from further examples and from a discussion of remedies. Nonetheless, Williamson does raise some disturbing questions about the will of America to enforce its laws, to control its borders, and to define and protect its identity.