The introduction established the main argument of the book, which is that the U.S. Navy’s charts and its chart-making throughout the nineteenth century were integral to the expansion of American oceanic empire even as such effort exposed the limits of science practice, seafaring, and war-making in a dynamic, dangerous marine environment. The Navy and the broader American maritime world’s encounter with the ocean, mediated through science, was integral to the way mariners, navigators, and naval officers thought of an emerging maritime empire first in commercial terms and, by the late nineteenth century, in new geo-strategic terms. The introduction also places the larger work within the historiographies of military, maritime, and naval history as well as environmental history and the history of science and cartography, seeking to establish historiographical and methodological bridges among these sub-fields.