Scholars of British America generally conclude that the early eighteenth-century Anglo-American empire was commercial in economics, liberal in politics, and parochial in policy, somnambulant in an era of "salutary neglect," but Stephen Saunders Webb here demonstrates that the American provinces, under the spur of war, became capitalist, coercive, and aggressive, owing to the vigorous leadership of career army officers, trained and nominated to American government by the captain general of the allied armies, the first duke of Marlborough, and that his influence, and that of his legates, prevailed through the entire century in America.

Webb's work follows the duke, whom an eloquent enemy described as "the greatest statesman and the greatest general that this country or any other country has produced," his staff and soldiers, through the ten campaigns, which, by defanging France, made the union with Scotland possible and made "Great Britain" preeminent in the Atlantic world. Then Webb demonstrates that the duke's legates transformed American colonies into provinces of empire. Marlborough's America, fifty years in the making, is the fourth volume of The Governors-General.