Book excerpt: The United States of Mestizo is a powerful manifesto attesting to the fundamental changes the nation has undergone in the last half-century. Writer Ilan Stavans meditates on how the cross-fertilizing process that defined the Americas during the colonial period--the racial melding of Europeans and indigenous peoples--foretells the miscegenation that is the most salient profile of America today. If, as W.E.B. DuBois once argued, the twentieth century was defined by a color fracture at its core, Stavans believes the twenty-first will be shaped by a multi-color line that will make us all a sum of parts.