The Cleland mss., 1911-1946, consists of the papers of botanist Ralph Erskine Cleland, 1892-1971. They consist chiefly of correspondence with prominent scientists on Oenothera, evening primrose.
The Aristotle mss., 1603-1704, consists of commentaries on the works of Aristotle. At least half of the volumes concentrate on logic, but other subjects are covered as well, including physics and general philosophy.
The Moenkhaus mss., 1892-1918, consist primarily of the correspondence of zoologist William J. Moenkhaus, 1871-1947, former professor at Indiana University.
The Parkin mss., 1900-1928, are letters from Thomas Parkin, British ornithologist, from prominent ornithologists, artists, novelists, statesmen, playwrights and authors.
The Lesueur mss., 1819-1830, consist of eight letters to Charles Alexandre Lesueur, 1778-1846, artist and naturalist, and bills of lading for minerals shipped by or to Lesueur.
The Eigenmann mss., 1851-1971, consists of the papers of Carl H. Eigenmann, 1863-1927, ichthyologist, and his wife, Rosa Smith Eigenmann, 1858-1947, ichthyologist.
The Medieval and Renaissance mss., 700-1600, consists of individual items acquired from time to time either as a gift or purchased from a variety of sources.