Seigenthaler, John.James K. Polk. Holt, 2003. A concise portrait of a little-known president who accomplished a lot.
Sellers, Charles G., Jr.James K. Polk. Princeton University Press, 1957-1966. 1969-1972. Volume 1 deals with the so-called Jacksonian period, volume 2 deals with Polk's presidency and U.S. territorial expansion.
Weaver, Herbert, and P. H. Bergeron, eds.The Correspondence of James K. Polk. Vanderbilt University Press, 1969-1972. Documents Polk's life in Tennessee, his terms in Congress, and his career as chief executive.