In Frontier Country , Patrick Spero addresses one of the most important and controversial subjects in American history: the frontier. Countering the modern conception of the American frontier as an area of expansion, Spero employs the eighteenth-century meaning of the term to show how colonists understood it as a vulnerable, militarized boundary. The Pennsylvania frontier, Spero argues, was constituted through conflicts not only between colonists and Native Americans but also among neighboring British colonies. These violent encounters created what Spero describes as a distinctive "frontier society" on the eve of the American Revolution that transformed the once-peaceful colony of Pennsylvania into a "frontier country." Spero narrates Pennsylvania's story through a sequence of formative but until now largely overlooked confrontations: an eight-year-long border war between Maryland and Pennsylvania in the 1730s; the Seven Years' War and conflicts with Native Americans in the 1750s; a series of frontier rebellions in the 1760s that rocked the colony and its governing elite; and wars Pennsylvania fought with Virginia and Connecticut in the 1770s over its western and northern borders. Deploying innovative data-mining and GIS-mapping techniques to produce a series of customized maps, he illustrates the growth and shifting locations of frontiers over time. Synthesizing the tensions between high and low politics and between eastern and western regions in Pennsylvania before the Revolution, Spero recasts the importance of frontiers to the development of colonial America and the origins of American Independence. Named one of the best books of 2017, Philadelphia Inquirer "Spero ... spins a fascinating tale of history in Pennsylvania's backwaters." Harold Brubaker, Philadelphia Inquirer "This fascinating book will undoubtedly - and deservedly - remain a standard work on the topic." - Journal of the American Revolution " An ambitious book ... Anyone interested in early Pennsylvania or the history of the American frontier will find much to admire in this important book." Judith Ridner, Journal of Interdisciplinary History [A] thought-provoking new study of Pennsylvania's wars with neighboring peoples over its first hundred years ... [that] breathes new life into the age-old problems of frontiers, power relations, and forms of government. There is a great deal here worth thinking about, and worth thinking about carefully." William H. Carter, Western Historical Quarterly "Spero ... offers a compelling argument for renewed attention to early American conceptions of the frontier." - James Rice, Journal of Southern History "Engagingly written and impressively documented" - Jack Brubaker, Intelligencer Journal, LancasterOnline.com "A must read for anyone seriously interested in colonial history." StrayegyPage.com "Scholars of early Pennsylvania, the American Revolution, and especially of "frontier studies" will find Spero's book immensely valuable to understanding the intersection of all three." - Pennsylvania History " Frontier Country sets an outstanding example of the ways that these forms of micro- and macroanalysis can be effectively combined in literary, history, and cultural studies, with persuasive and compelling results." - Keri Holt, Early American Literature "[Spero's] novel formulation of "frontiers" raises the question of where else historians of early America and the Atlantic World might find similar conditions." - American Historical Review "Spero's love of language manifests in his lucid writing style and the way he unpacks his terms, which forms the argument of his book. He breathes life into linguistic relics. " - Ohio Valley History Patrick Spero is the Chief Executive Officer of the American Philosophical Society. As a scholar of early American history, he specializes in the era of the American Revolution, and has published over a dozen essays and reviews on the topic. He is the author of Frontier Rebels: The Fight for Independence in the American West, 1765–1776 (Norton, 2018), and of Frontier Country: The Politics of War in Early Pennsylvania , and The American Revolution Reborn: New Perspectives for the Twenty-First Century , both of which are available from the University of Pennsylvania Press.