Consists of works, correspondence, diaries, documents, photographs, maps, scrapbooks, miscellaneous material, and printed matter by and about mountaineer J. Monroe Thorington (Princeton Class of 1915), as well as some papers of other people.

Consists of letters and miscellanea of the educator, merchant, and first secretary of the Continental Congress Charles Thomson (1729-1824).

Consists of documents and correspondence of Smith Thompson (Princeton Class of 1788) covering, for the most part, the years (1823-1843) when he served on the U.S. Supreme Court.

Consists of selected papers of Thompson, including 27 scrapbooks of clippings (1884-1941) of his columns and articles written while he was a Washington correspondent, book reviewer, and editor of the New York Times (1899-1921) and, later, a writer in Philadelphia for the Public Ledger (1921-1922) and Commonweal (1930-1931).

Consists of manuscripts, correspondence, documents, photographs, scrapbooks, and miscellaneous research material of librarian/archivist Milton Halsey Thomas, including research material for several of his historical publications.

The Lewis Thomas papers consist primarily of files from the years (1973-1983) that Thomas (Princeton Class of 1933) spent as president and, later, chancellor, of Memorial Sloan-Kettering Cancer Center in New York City. These contain general correspondence with doctors, drafts and reprints of his essays and books, files of lectures, presentations, and awards, and files of scientific organizations with which he was involved. There are also drafts and reprints of early scientific papers (which pre-date his years at MSKCC).

Consists of selected papers of George F. Thomas, professor of religious thought (1940-1968) at Princeton.

Consists of letters by American novelist Benedict Thielen (Princeton Class of 1923) to Frederic Roderigo Gruger, Jr.