Though several historians had published works on America's westward expansion prior, Paxson's Pulitzer Prize winning study was groundbreaking in its complete and unified presentation. Beginning with a survey of the frontier at the end of the French and Indian War and proceeding to follow the frontier westward until the close of the period of settlement in about 1890, Paxson's cross-sectional method carries the narrative in a wide windrow of detail, serving as a detailed and scholarly synthesis of the fragmentary work of previous historians. An essential title for any study of American history.