A nation of immigrants, to be sure, but not just any immigrants. From the moment they managed their own affairs, well before political independence, Americans were determined to select who might join them, and they have remained so ever since. Immigration policy, broadly conceived in this book to encompass not only entry but also related processes that affect the nation's composition, thus emerged from the outset as a major instrument of nation building, equivalent in the fashioning of the United States to the amalgamation of diverse regions in the making of the United Kingdom, France, or Spain. Although as historical constructs all nations in some sense make themselves, the very nature of the immigration process provided the Americans with unusual attitude in doing so, and hence theirs may properly be termed "a nation by design."