Beyond methodology, I would like to highlight the temporal scope that the book handles. The period of analysis is broad, ranging from the mid-19th century to the present, always focused on the Bom Retiro neighborhood, as the research site. Despite being so broad, the study works because there is a thematic thread that ties everything together: the relationship between health, migration, and the urban environment. Thus, there is a central question that holds the book together, revolving around the practices of health and illness carried out by the state and its agents, and how people engage in everyday health practices. In this way, the book distances itself from a purely top-down perspective on public policies, bringing us closer to how these policies are actually carried out and how the residents of Bom Retiro receive them and act upon them.

Another important aspect is the spatial approach, since the book also analyzes how people and the state construct the space of Bom Retiro, and, at the same time, how that space shapes people and their health. Bom Retiro was and continues to be a central neighborhood in the urban social configuration, particularly for migrants, as well as for the construction of the health and illness of the population of São Paulo.

The book employs the analytical notion of “residues” (material, political, and social), which allows it to address historical continuities. The idea of residues refers simultaneously to structures of repetition and to residual subjects. For the history of social sciences (particularly anthropology), the category of residues is not an empty signifier; it carries connotations, a certain haunting meaning provocative at the same time. But here they acquire situated meanings, linked both to social practices and to the research problem.

Chapter 5, in particular, puts into practice what the introduction announces, in the sense that it traces in the present the residues of past ideas which, despite biomedical advances, continue to prevent improvements in health outcomes in Bom Retiro. To reach this conclusion, the book traces—from the 19th-century General Disinfectory to current Zika prevention campaigns—the tensions between the state, health officials, and the residents of Bom Retiro. And there it shows how the “residues” of public health workers’ attitudes toward migrants persist today, insofar as the migrant population continues to be perceived as the source and cause of various diseases. In contrast, the research highlights the influence of the urban environment, broadly conceived, as key to understanding the spread of disease.