Goetzmann, William H.Exploration and Empire. Texas State Historical Association, 1993. Pulitzer Prize-winning account of exploration of American West; first published in 1966.
Tocqueville, Alexis de.Democracy in America. HarperCollins, 1988. Frenchman's keen observations on America during presidency of Andrew Jackson; originally published in 2 volumes, 1835-1840.
Adams, James Truslow, and others, eds.Dictionary of American History. Scribner, 1976-1978. 1996. Articles by experts; concise edition published in 1983.
Boorstin, Daniel J.The Americans. Random House, 1958-1973, 1984-1985. How Europeans became Americans.
Wilentz, Sean.The Rise of American Democracy: Jefferson to Lincoln. W. W. Norton., 2005. A lengthy and detailed account of the growth of democracy in the United States, culminating with the debate over slavery and the subsequent Civil War.