Anthropology and history found each other, once again, in the 1980s and 90s, and the intellectual offspring of this encounter continue to grow in important and interesting directions. In The Science and Politics of Race in Mexico and the United States, 1910–1950 Karin Alejandra Rosemblatt offers an extensive and deeply nuanced history about the importance of ideas of diversity and unity among transnational networks of intellectuals and state actors in north America. This is not the first time scholars have looked hard at the history of anthropology in Mexico and/or the United States, at the role of anthropologists in policy making and institution building, or at the place of their ideas in the conformation of national political projects. This is, however, the most complete discussion to date, benefitting both from a penetrating reading of the extensive secondary literature in history and anthropology, as well as access to an ample set of historical archives, documents and publications from Mexico and the United States. Rosemblatt's success at bringing these resources together into a coherent narrative across national and disciplinary borders is impressive.

The book is structured in two parts. The first deals with the years 1910–30 (roughly), a time marked by the upheaval of the Mexican Revolution, the First World War, and mass migration. The first few decades of the twentieth century saw the consolidation of university anthropology departments and federal government agencies dealing with Indigenous populations in Mexico and the United States. Some outlines of this transnational history have been traced before, and Rosemblatt expands our understanding more than changes it. She skilfully uses archival material from the migration studies projects of the National Research Council and Social Science Research Council to identify conversations, collaborations and conflicts among US and Mexican scholars who grappled with ideas of eugenics, evolution, nationalism and cultural relativism. In Chapter 1 the book provides a rich discussion of the effort in Mexico to forge a nation by actively studying and integrating Indigenous people and culture – a political and intellectual project known as indigenismo. In Chapter 2 the book traces cross-border discussions about migration and race as they played out in the planning and funding processes of the National Research Council and Social Science Research Council. Throughout these chapters and the entire book we see how ideas about the nation and its subgroups took shape in engagements beyond the nation.

Part 2 of the book deals with 1930–50, a period of socioeconomic crisis, development and recovery in which federal governments in Mexico and the United States deployed anthropology to define social problems and expand governance. The transborder scale of the book comes into sharp focus in Chapter 3, which follows the work of US Commissioner of Indian Affairs John Collier and his colleagues as they conceptualised and enacted policies to govern Native groups in the United States, managed the Poston internment camp for Japanese-Americans during the Second World War, and built on these experiences to conceptualise the role of anthropology in the informal empire of the United States that emerged in the 1940s. Once again this is transnational history, and Mexican intellectuals are folded into this story through their influence shaping Collier's ideas and proposals. Chapter 4 returns to Mexico during the rule of President Lázaro Cárdenas in the 1930s, looking at the influence of socialist concepts of class and nation, at how intellectuals and state agents approached socioeconomic and cultural diversity, and at how indigenismo took new forms.

The book's strength lies in its ability to span Latin American and US history, documenting transnational networks of intellectuals, ideas and institutions, especially as they crossed borders of language, state practice and culture between the United States and Mexico. The thorough reading by an historian of a wealth of untapped or underused archives in both countries (such as that of the Instituto Indigenista Interamericano, opened in 2009) sets this book apart. It is, in the end, a history of ideas, and while we do get some sense of the institutions in which these ideas were produced and implemented, we do not see what effects these ideas actually had on the people that they depicted. Many questions arise about the social history of these ideas of race and science. Did some form of self-rule take shape within the walls of Poston internment camp, where Collier implemented his anarchist-tinged ideas of the autonomy and democracy of small-scale society? Did the indigenistas succeed in promoting economic development while conserving ‘efficient’ cultural elements of local Indigenous groups in Mexico? Can we connect this transnational anthropology to the much more recent resurgence of Indigenous social movements and identities in Mexico and the United States? This book provides the elements needed to advance research in these areas of social history and anthropology.

Rosemblatt does an excellent job of presenting a very complicated intellectual landscape by continuously rebalancing the particular details of this history with the universal tendencies made evident by her transnational and historical comparative approach. This is the relation between data and analysis present in all disciplines and arguments, and in anthropology it takes the form of a blend of ethnography and ethnology. This blend can be seen in the work of the anthropologists that Rosemblatt studies as well as in her own telling of this history. We see in this book many instances of this: how Mexican anthropologists took on the role of producing data about the historical particularities of Indigenous groups in that country while US anthropologists presented interpretation and theory; how a more liberal vision of cultural autonomy was countered by an evolutionary understanding of modernisation that carried all groups along; how US functionalists identified processes of total social change and Mexican indigenistas sought to document and conserve cultural difference while promoting economic change. In Rosemblatt's view, this is the question of whether modernity is understood as singular or plural, who sees it in which way, and why.

Rosemblatt continues to push this line of questioning, suggesting the importance of addressing the mechanisms by which comparisons are made, and similarities and differences are measured. Citing Ann Stoler, she points out the statistical techniques through which the ‘commensurability’ of cultures is constructed, and later in the book identifies three forms of aggregation: taxonomic; encyclopaedic; numerical (p. 138). This analysis is brought to bear on a particular historical moment in Mexican anthropology in the 1930s that was marked by the production of an immense amount of data about culture, economy, family and other dimensions of local culture, which can be seen as the realisation of Manuel Gamio's 1916 vision of an ethnographic statistics useful for nation-building and state formation. An emphasis on producing numerical data, for example, privileged realms such as the economy over, say, religion or art. The book hints at these possible contributions to history and anthropology of statistics, but does not develop them with a discussion of that literature, once again opening a path for a promising research agenda.

The Science and Politics of Race is thorough, insightful and nicely penned, making the complicated material in the book accessible without simplifying it. This is a book that would be most useful for graduate courses concerning the history or anthropology of science, race, state formation and nationalism, but it would also be appropriate for the upper-division history of anthropological courses that are common in many undergraduate anthropology programmes.