Collection
- Manuel Komroff papers, 1897-19791
- Mariia Vladimirovna Volkonskaia Papers, 1858-19591
- Mark Aleksandrovich Aldanov Papers, 1926-19571
- Marshall MacDuffie Papers, 1945-1962, bulk 1945-19531
- Mary Lasker papers, 1940-19931
- Metropolitan Platon Papers, 1917-19641
- Meyer Schapiro letters and manuscripts of Whittaker Chambers and James Thomas Farrell, 1923-19911
- Michael Sorkin papers and architectural drawings, 1952-2020, bulk 1978-20201
- Michael T. Florinsky Papers, 1914-19181
- Mikhail L'vovich Kantor Manuscripts, 1904-19681
- Mikhail Vasil'evich Karkhanin Papers, 1915-19591
- Mira Edgerly Korzybska papers, 1850-19601
- Morton H. Fried papers, 1945-1996, bulk 1961-19861
- Mother Mariia Papers, 1912-19551
- Nancy Wechsler Papers, 1935-20071
- Nataliia Apollinarievna Logunova Papers, 1913-19721
- Nicholas Murray Butler papers, 1891-19471
- Nikola Tesla papers, 1894-19311
- Nikolai Nikolaevich Chebyshev Papers, 1887-19371
- Nikolai Nikolaevich Kostylev Papers, 1905-19501