The immigrant rights movement is one of the most dynamic social movements in the United States. In the spring of 2006, across the country millions of mostly Latino immigrants participated in some of the largest civil rights demonstrations in American history. In this timely and highly anticipated book, Chris Zepeda-Millán analyzes the background, course, and impacts of this unprecedented wave of protests, highlighting their unique local, national, and demographic dynamics. He finds that because of the particular ways the issue of immigrant illegality was racialized, federally proposed anti-immigrant legislation (H.R. 4437) helped transform Latinos' sense of latent group membership into a racial group consciousness that incited their engagement in large-scale collective action. Zepeda-Millán shows how nativist policy threats against disenfranchised undocumented immigrants can provoke a political backlash--on the streets and in the ballot box--from not only "people without papers," but also naturalized and U.S.-born citizens. Latino Mass Mobilization is an important intervention into contemporary debates about race, immigration policy, Latino politics, and immigrant activism in the U.S.