<p>This doctoral thesis offers a big-picture view of the material and cultural history of science in colonial Latin America. It argues that science in the Viceroyalty of New Spain can be best understood not as isolated from centres of European culture, but rather as a productive extension of Old World and Indigenous techniques for observing and quantifying nature. Moreover, it also shows that Mexico City quickly became a central node in the production and funding of science within the Spanish Empire, rather than being peripheral to early modern scientific discourse. It examines the nerve centre of Spain’s overseas territories, the viceregal capital of New Spain, as a hub not only of funding but also of vibrant activity for Spanish and Novohispanic science from 1535 to 1700. Current historians of Spanish and Spanish-colonial science have demonstrated that, in contrast with depictions in older histories of early modern science, Spain was an active producer of technologies of discovery and natural resource extraction as well as works on theoretical and applied mathematics. During the sixteenth and seventeenth centuries, the Spanish Crown and other private corporate bodies—including the religious orders—supported the production of new forms of knowledge. I will refer to these throughout as “science” and to its practitioners as “scientists.” Scientists who feature prominently in this thesis set precedents for later scientific endeavours in Latin America and Europe. Sixteenth-century botanist Francisco Hernández, cartographer Francisco Domínguez y Ocampo, and astronomer Jaime Juan established some of the first large-scale observations and records of an expansive New Spain. In the following years a diverse set of seventeenth-century hydraulic engineers fielded a variety of solutions to a complex set of topographical and political issues in the viceregal capital. At the same time, a lively group of astronomer-mathematicians contributed to an increasingly global network of scientific discourse. Many of these scientists and intellectuals owned notable personal libraries. This thesis examines the implications of mobile books—locally-produced as well as European—as they contributed to the production of new knowledge in the Americas, Asia, and Europe. Powerful Spanish and criolla women patronized or supported the promulgation of scientific writings in New Spain. Additionally, indigenous authors disseminated the concepts of early modern science to their readers within colonial-era Nahua chronicles. Hobbyists also interacted with professional and well-known scientific thinkers at local discussion clubs or via correspondence and improvised their own instruments based on available texts. Local book printers and authors of popular early modern science works are also included in this investigation as they played key roles within the social networks of science. This thesis relies on archival manuscript sources while synthesizing the rigorous scholarship of many specialists in order to tell the story of how a major sixteenth-century Spanish colonial city possessed the resources to engage in a variety of early modern scientific undertakings. It re-examines documents concerning the history of science in New Spain in order to ask new questions about the role of scientists’ instruments, personal book collections, and correspondence with colleagues abroad upon the influence of their professional writings. By assembling a selection of key case studies, the thesis shows that sixteenth-century royal investments in scientific institutions on the Iberian Peninsula bore fruit in New Spain during the late 1500s and the 1600s as diverse communities of scientists flourished in Mexico City and its seaports. In sum, this is a study of the movement of early modern scientists, their tools and ideas as well as the concentration of these resources in the geographical and cultural surroundings of New Spain.</p>