The International Institute of Social History in Amsterdam is an important centre for research in the field of social history:
"The International Institute of Social History (IISH) is the world's largest documentation and research centre in the field of social history. Since its foundation in 1935, the institute has dedicated itself to the collection, preservation and availability of the heritage of social movements worldwide. The institute is independent and reliable, which makes it a natural depository of the frequently threatened cultural heritage of the labour movement and other emancipatory groups and currents. The research department of the institute focuses on the history of labour relations and organizes international projects in this field. The collection (archives, library and audio-visual materials) takes up well over 30 miles of shelf room. The IISH is an institute that comes under the Royal Netherlands Academy of Arts and Sciences (KNAW)."
The ISSH holdings contain several Yiddish materials:
Yiddish Collections Guide:
"The IISH has a unique and manifold collection of Yiddish material consisting of books, brochures, periodicals and pamphlets of the early Jewish socialist and anarchist movement in Eastern and Western Europe. In addition to this printed material the Institute has a large collection of Bundist (election) posters, photo's and prints, mainly from interbellum Poland. Next to this printed and visual material the IISH owns part of the Bund-archives viz. the incoming material from the Bund Foreign Committee in Geneva as well as material from the Central Office of the Bund in Geneva. The IISH acquired the Bund archive in 1935, most of the other Yiddish material comes from the collections of Max Nettlau, Pierre Ramus and Rudolph Rocker. Though the Bund archive was the first acquisition of the IISH after its foundation in 1935 this collection, as well as the the other Yiddish material had to wait for the expertise and dedication of prof. dr R. Fuks-Mansfeld to be properly catalogued and arranged. The IISH now has one of the largest accessible collections in this field."
Yiddish letters can be found in several archives which were acquired by the IISH in the course of time. Some of these are from archives bought or deposited in the IISH after the coming to power of the German National-Socialist Party in 1933. [...] After World War II, many important anarchist archives that include Yiddish letters came from the U.S.A. These included the archive of the German anarchist Rudolf Rocker and the Russian-American anarchists Senya Fléchine, Alexander Berkman, and Boris Yelensky. Thanks to Dr Rena Fuks-Mansfeld, more than 700 of these Yiddish letters are now accessible through a database. The files can be searched on author, sender, destination, and period of time. A short abstract of every letter is provided.
Yidishkayt catalogue search:
All Yiddish printed materials (books, brochures, journals, flyers) in the collections of the IISH can be found under the denominator Yidishkayt in the catalogue.