Correspondence, memoranda, speeches, articles, notes, personal miscellany, legal records, biographical material, clippings, printed matter, and other papers relating to Bonaparte's service as U.S. attorney general and U.S. secretary of the navy during Theodore Roosevelt's presidential administration and to the Progressive Party and Republican Party. Subjects include civic, charitable, and political affairs in Baltimore and Maryland. Documents his work with Catholic University of America, Washington, D.C.; Enoch Pratt Free Library, Baltimore, Md.; Harvard University Board of Overseers; Maryland Board of State Aid and Charities; National Civic Federation; National Civil Service Reform League; and National Municipal League. Legal records of Bonaparte, his family, and clients cover the period 1760 to 1920.

Correspondents include Louis Dembitz Brandeis, Champ Clark, Richard Henry Dana, Charles William Eliot, James Rudolph Garfield, Elbert H. Gary, James Gibbons, Henry Cabot Lodge, Theodore Roosevelt, Carl Schurz, William H. Taft, Benjamin R. Tillman, Richard M. Venable, Owen Wister, and Clinton Rogers Woodruff.