My research attempts to explore two critical dynamics that interact and are directly implicated in rising inequality in the United States: increasing levels of international migration and persistent residential segregation. By the late 20th century, every developed country has become an immigrant-receiving society, drawing migrants primarily from the developing world. In Beyond Smoke and Mirrors: Mexican Immigration in an Age of Economic Integration, I explore the role of immigrants in the economies of North America, whereas in Return to Aztlan, I focused on the social mechanisms promoting and sustaining emigration from Mexico to the United States, while providing a critique of past U.S. policies and avenues for future reform. At the same time as these events are unfolding, we find that African Americans remain uniquely segregated in American cities. As I showed in American Apartheid, segregation figures prominently in explanations for black underachievement. In The Source of the River I show how it interacts with shifts in the U.S. income distribution to yield a rising concentration of poverty that, in turn, intensifies social disorder and violence that undermines the health of African Americans, reduces their life expectancy, and impairs their cognitive development. My most recent book, Categorically Unequal, dissects the historical and contemporary patterns of racial inequality in the U.S.