Papers relating to Henry Adams, his wife, Marian (Hooper) Adams, and his niece, Louisa C. (Hooper) Thoron. The bulk of the collection consists of family correspondence, 1848-1918, including letters from Adams, 1861-1918, to his brother-in-law, Edward Hooper; his niece; and Ward Thoron (who later married Louisa Hooper). Many of these letters were written from his home in Washington, D.C. or from England and France and include comments about his activities, various individuals including his friends and political figures, and current research projects. The collection also includes two items written by Henry Adams: an address he delivered to his Harvard classmates in 1858, and the poem, "Radical Club," published with the by-line, "An Atom, " probably written by Adams. The correspondence of Marian Adams includes some letters to her sister Ellen Sturgis Hooper and Fanny Chapin, her friend and later sister-in-law, and some Hooper familiy correspondence, 1848-61. Records relating to the Adams Memorial, located in Rock Creek Cemetery in Washington, D.C., include correspondence and plans, 1962-92, concerning the redesign of the landscaping near the memorial. Other materials in the collection are: property plans, 1884-86, outlining the land owned by Henry Adams in Beverly, Mass., genealogical information about the Adams and Quincy families, a commonplace-book, 1877-1908, kept by Theodore F. Dwight, Adams's assistant, and two watercolors probably by Henry Adams.