Replenished Ethnicity explores how large-scale Mexican immigration to the US shapes assimilation processes. Jiménez examines how immigration patterns influence the construction of ethnic identity among Mexican Americans as well as their position in the ‘racial and ethnic landscape’ (p. 23) of the US.

To address these two primary aims, Jiménez engaged in fieldwork in the cities of Santa Maria, California and Garden City, Kansas. He carried out interviews and participant observation with the descendants of Mexican immigrants whose families arrived to the US before 1940. This group is referred to as ‘later-generation’ Mexican Americans.

First, Jiménez contends that early assimilation models are limited in their ability to understand the experiences of ‘later-generation’ individuals. These early models – largely developed to understand European migration at the beginning of the 20th century – posit that after a few generations, the children and grandchildren of immigrants assimilate into American society and their ethnic identity takes on diminishing importance in their everyday lives to become ‘symbolic, optional, and inconsequential’ (p. 21). Jiménez asserts that these straight-line assimilation models make a misleading assumption; they presume that immigration eventually stops. He persuasively argues, however, that the continued and uninterrupted immigration of Mexicans to the US over the last century facilitates later-generation Mexican Americans to actively engage in the practice of ethnicity.

Jiménez's fieldwork demonstrates that the presence of recent immigrants enables access to ethnic practices and ‘raw materials’ (p. 137) that make it possible for later-generation Mexican Americans to construct a salient ethnic identity. He states that Mexican immigration encourages opportunities to speak Spanish in the workplace and on the street, shapes access to Mexican goods, grocery stores and restaurants, and elicits the development of professional and romantic relationships between immigrants and later-generation Mexican Americans. Immigration also encourages the continued construction and re-interpretation of ethnic boundaries. Importantly, Jiménez argues that not only the presence of large-scale immigration but also ideologies of multiculturalism and discourses of nativism shape the willingness of later-generation individuals to attach to an ethnic identity.

Secondly, Jiménez challenges the grave conclusions of more recent assimilation models that argue that ethnic and racial discrimination prevent Mexicans from assimilating to the mainstream and consign them to the political and economic margins of society. Jiménez claims that these models do not acknowledge that later-generation Mexican Americans have experienced structural assimilation in terms of socioeconomic status, education, residential location, intermarriage and civic participation (p. 99). Thus, although Mexican American assimilation has occurred more slowly than it has for the ancestors of European immigrants, Jiménez's research illustrates that they have demonstrated significant gains in mobility, even in the face of discrimination.

To conclude, Jiménez maintains that ‘… without taking immigrant replenishment into account, we find a poor fit between Mexican-origin experience on the ground and the existing theoretical perspectives that explain it. Simply too much evidence of assimilation exists for us to regard ethnic Mexicans as an aggrieved minority. Yet ethnicity remains far too important in their lives to regard them as an assimilating ethnic group’ (p. 254). Replenished Ethnicity challenges the adequacy of assimilation models and demonstrates that to understand ethnic identity formation and assimilation trajectories of later-generation Mexican Americans it is imperative to theorize the role played by large-scale Mexican immigration to the US. Jiménez's work will be of particular interest to sociologists, anthropologists and migration scholars who are dissatisfied with the ability of existing assimilation models to capture the nuanced integration trajectories experienced by Mexican Americans.