Brief Description: The papers relate to Weinreich's work in the fields of Yiddish linguistics, literature, and Jewish folkore, education, history, as well as to his organizational activities at YIVO. Materials on Yiddish language and linguistics. Linguistic maps of Yiddish. Notes on orthography, anglicisms. Material from Joshua Fishman's project "Survey of Language Resources of American Ethnic Groups." Material from the Fifth International Congress on Linguistics, 1939. Notes and manuscripts on Old Yiddish, modern Yiddish, Alsatian Yiddish. Proofs and notes for Uriel Weinreich's *Yiddish-English English-Yiddish Dictionary*. News clippings about the *Groyser yidisher verterbukh* (The Great Yiddish Dictionary). Notes on other dictionaries and glossaries. Notes and cards relating to Weinreich's *History of the Yiddish Language*. Materials of the Atran Foundation such as correspondence, memos, reports. Correspondence about the Columbia Linguistics Department, 1967. Manuscript by Judah Joffe on linguistics. Materials relating to the YIVO Institute. Correspondence, 1940-1968. Speeches by Max Weinreich about YIVO, 1941-1951. Project proposals for a YIVO graduate school. YIVO Annual reports. Records of the YIVO Planning Commission of YIVO. Plans for the YIVO Center for Advanced Jewish Studies. Syllabi of YIVO courses. Materials relating to topics in Jewish history. Articles about Jewish immigration to the U.S.. Jewish organizations in America. Reports and papers from conferences on Jewish history. Copies of historical documents, 18th-19th centuries. Manuscript on Jews in Lithuania, on Jewish situation during World War II. Manuscript of *Hitler's Professors*, by Max Weinreich, published by YIVO in 1946. Materials relating to Jewish folkore and literature. Proceedings of the first annual conference on Jewish folkore, Israel 1959. Folktales, Yiddish poems, Yiddish plays, Yiddish song sheets. Uriel Weinreich's bibliography on Sholem Aleichem, 1953. Materials for Max Weinreich's course at YIVO on "Basic Works of Jewish Literature." Notes and manuscripts by M. Weinreich on Mendele Moykher Sforim. Teaching materials. Roll books, attendance sheets, exams, term papers, course outlines for courses given at City College of New York and at UCLA in Los Angeles. Correspondence of Max Weinreich with Hannah Arendt, Martin Buber, Simon Dubnow, Rachel (Shoshke) Erlich, Joshua Fishman, Rudolf Glanz, Abraham Golomb, Chaim Grade, Szmerke Kaczerginski, Moses (Moyshe) Kligsberg, Leibush Lehrer, Itzik Manger, Shlomo Noble, David Pinsky, Melech Ravitch, Dov Sadan, Pinchas Schwartz, Isaac Bashevis Singer, Abraham Sutzkever, Zosa Szajkowski.