This limited series tells the story of the trans-Appalachian frontier. The opening and closing of the settlement frontier is the subject of each volume in the series, though each author takes an individual approach to that story. Each volume begins with the world that existed when Europeans made contact with native peoples. Each describes and analyzes the themes associated with the special circumstances of the individual territories, later states. Each concludes with the closing of the frontier, as each author interprets that concept. The books in the series are aimed at the widest possible audience of individuals interested in the formative history of the United States.