When the invading British army burned the congressional library in Washington, D.C. in 1814, an outraged Jefferson promptly offered his own library to Congress to replace the one that was lost. (He did not simply donate the books as he was deeply in debt and could use the money.) At the time of the purchase, Jefferson’s collection contained 6,487 books in the fields of politics, history, science, law, literature, fine arts, and philosophy, and was recognized as one of the finest private libraries in the United States. The purchase was authorized by Congress on January 26, 1815, for the sum of $23,950. The handwritten catalog that Jefferson sent to Congress along with his books was retained by the Librarian of Congress, but was subsequently lost.
A fire at the Library of Congress in 1851 destroyed many of the Jefferson books (along with 30,000 other volumes and original portraits of the first five presidents). The remaining volumes have been assembled as a unit in the Rare Book and Special Collections Division. Many books bear Jefferson’s ownership markings as well as the original Library of Congress bookplates and classification.
In 1942, as part of the bicentennial commemoration of Jefferson’s birth, the Library of Congress commissioned E. Millicent Sowerby to compile an annotated bibliography of the 6,487 books Jefferson sold to Congress. A five-volume work, The Catalogue of the Library of Thomas Jefferson, was published between 1952 and 1959, and a transcribed electronic version of Sowerby’s catalogue will soon be available.
On LibraryThing, you can see exactly what books Jefferson owned. Jefferson was added to the Library Thing database as an honorary dead member. Currently, 5,653 titles from his library have been entered into the database. You can access his member profile here and see his catalog of books here. You can also learn more about the sale of his personal library to Congress on the Monticello website, here.