A positive critique of three studies on cultural assimilation of Mexican Americans ("Dimensions of the New Immigration to the United States and the Prospects for Assimilation" by Douglas Massey, a series of articles by Miriam Wells, and "Language, Mexican Immigration, and the 'Human Connection': A Perspective from the Ethnography of Communication" by Jose Limon) argues that three key terms in assimilation studies--biologism, primitivism, and voluntarism--need replacement with a broader sense of agency, the analysis of cultural practices, and the study of racism. Voluntarism suggests that the assimilation process, both successes and failures, involve formally free choices within a socially given opportunity structure and should be displaced, in the author's view, by the analysis of racism. Primitivism suggests that assimilation is the movement from an authentic culture that is regarded as if it were a relic to be preserved just as it was, when, in fact, cultures undergo ongoing processes of change, making the notion of linear movement of assimilation from Mexican to Anglo problematic. Biologism suggests that people, as they become middle class, follow middle class norms of family size and occupation and conflates with class and culture, for such people may not be assimilated, but simply middle class. (NEC)