A fascinating ethnography of microbes that opens up new spaces for anthropological inquiry  The trillions of microbes in and on our bodies are determined by not only biology but also our social connections. Gut Anthro tells the fascinating story of how a sociocultural anthropologist developed a collaborative “anthropology of microbes” with a human microbial ecologist to address global health crises across disciplines. It asks: what would it mean for anthropology to act with science? Based partly at a preeminent U.S. lab studying the human microbiome, the Center for Genome Sciences at Washington University, and partly at a field site in Bangladesh studying infant malnutrition, it examines how microbes travel between human guts in the “field” and in microbiome laboratories, influencing definitions of health and disease, and how the microbiome can change our views on evolution, agency, and life. As lab scientists studied the interrelationships between gut microbes and malnutrition in resource-poor countries, Amber Benezra explored ways to reconcile the scale and speed differences between the lab, the intimate biosocial practices of Bangladeshi mothers and their children, and the looming structural violence of poverty. In vital ways, Gut Anthro is about what it means to collaborate-with mothers, local field researchers in Bangladesh, massive philanthropic global health organizations, with the microbiome scientists, and, of course, with microbes. It follows microbes through various enactments in scientific research-microbes as kin, as data, and as race. Revealing how racial categories are used in microbiome research, Benezra argues that microbial differences need transdisciplinary collaboration to address racial health disparities without reifying race as a straightforward biological or social designation. Gut Anthro is a tour de force of science studies and medical anthropology as well as an intensely personal and deeply theoretical accounting of what it means to do anthropology today.  Cover alt text:Black background overlaid with a pink organic path suggestive of a human digestive system. Title appears within the guts as if being processed.