Collection
- Otto Rank Association records, 1934-19931
- Otto Rank papers, 1903-1988, bulk 1903-19401
- Parks Council records, 1920s-1979, bulk 1925-19791
- Partido Comunista Mexicano records, 1933-19591
- Paul Oskar Kristeller papers, 1910-19891
- Paul R. Hays papers, 1910-19801
- Prince Paul of Yugoslavia papers, 1757-19761
- Records of the Committee to Honor the Memory of Vasilii A. Maklakov, 1957-19581
- Records of the Inter-University Committee on Travel Grants, 1958-19661
- Reid Hall records, 1919-19971
- Research in Contemporary Cultures records, 1939-1962, bulk 1947-19521
- Richard L. Simon papers, 1915-19921
- Roberts Brothers papers, 1838-1932, bulk 1882-18981
- Russkii Natsional'nyi Komitet Records, 1917-19601
- Samuel McCune Lindsay papers, 1877-19571
- Samuel S. Dale papers, 1810-19291
- School of Social Work Records, 1898-circa 2010s, bulk circa 1930s-1980s1
- Semenovskii Polk Records, 1720-19671
- Sergei Sergeevich Belosel'skii-Belozerskii Papers, 1700-19681
- Seth Low Junior College Records, 1928-19411