This volume makes a compelling case for centering circuits of experts and expertise in understanding Latin America's Cold War. Born out of a conference at Yale University in 2016, it follows the transnational trajectories of scientific, technological, and environmental experts during Latin America's “long Cold War,” shedding light on this crucial period beyond traditional Cold War narratives as well as contributing to histories of Latin American science, technology, and the environment.A lucid editors' introduction, an essay by Gilbert Joseph on the sea change in literature on Latin America's Cold War, and a conclusion by Eden Medina and Mark Carey on environment, technology, and science provide a comprehensive vision of the volume's stakes and contributions. The 11 historical chapters are organized into four, roughly chronological sections and cover diverse scientific and technological fields and projects, intersecting to varying degrees with histories of Argentina, Brazil, Chile, Colombia, Cuba, Mexico, Peru, and Puerto Rico from approximately the 1920s to the present.By tracing out the paths of experts in the production and circulation of expertise, these authors critique seemingly intransigent assumptions about the place of science, technology, and the environment in Latin America. While Latin American countries often have been seen as recipients of expertise from the United States and Western Europe, the authors of this volume challenge the directionality and place of expert circulation and knowledge production, as Thomas Rath does in his essay on the impact of Mexican responses to foot-and-mouth disease eradication programs on laboratory science and epizootic policies in Brazil, the United States, and the United Kingdom. Attentiveness to the local production of knowledge also reveals the place of Latin American experts in development projects like the Green Revolution, illustrated by Timothy Lorek's agronomists in Colombia's Cauca Valley. Scholars in this volume better locate this production in diverse inter-American exchanges, such as the “transnational contact zone” of the Inter-American Housing and Planning Center featured in Mark Healey's chapter (p. 200). Further demonstrating the multidirectional flows of Cold War expertise and expert politicking, Mary Roldán's chapter on education expertise illustrates the power of one expert's varied anticommunist discourse to marshal resources from across the hemisphere for his radiophonic schools.If the term Cold War suggests a bipolar world, this volume shows how experts, often because of their expertise, could forge unexpected connections across such geopolitical rigidity, as illustrated in Reinaldo Funes-Monzote and Steven Palmer's essay on the history of Cuban-Canadian cooperation on cattle breeding and in Andra Chastain's chapter on Chilean and French expertise in the construction of the Santiago metro and the role that it played in shaping political debates in Santiago and advancing French diplomatic aspirations. Opening up Cold War bipolarity also decouples scientific expertise from state dominance, seen in Emily Wakild's chapter on natural field scientists' resistance to developmentalism in the “middle landscapes” of the Peruvian Amazon and in Javiera Barandiarán's history of the privatization of Chilean environmental scientific expertise during the late twentieth century's neoliberal reforms (p. 262).Attentive to the porousness of the divide between cultural and political spheres and between scientific and technological ones, authors in this volume highlight entanglements of nonexpert culture and politics with scientific and technological projects, as demonstrated by Pedro Ignacio Alonso and Hugo Palmarola in their excavation of how the National Aeronautics and Space Administration's insignia design projected the scientific meaning of its satellite networks in Chile and by Fernando Purcell in his examination of the “concrete revolution” across South America and the necessity of crafting a popular imaginary for something as immaterial as electricity in order to support the construction of massive concrete hydroelectric dams (p. 222). Contributors also illustrate the political mutability of scientific knowledge and technological projects, made clear in Tore Olsson's unpacking of the Tennessee Valley Authority's power as an “idea” for both Left and Right in postrevolutionary Mexico (p. 75).Contributors to this volume do an excellent job of showing how a hemispheric program materialized out of transnational exchanges of expertise situated in local and national contexts; by doing so they advance scholarly agendas to construct a Latin American Cold War and to integrate histories of science, technology, and the environment. For this reviewer, the volume's successes gesture toward a need to reevaluate further how much the Cold War as a dominant historiographical concept explains and how much it obscures, particularly with regard to development as a response to structural phenomena and the continuities in transnational, inter-American scientific and technological networks from the nineteenth century onward. Ultimately, Latin Americanists working on different time periods will find this volume generative; scholars of science, technology, and the environment working on different geographical fields will recognize its contributions; and advanced undergraduates will find its essays stimulating.