From the website:
"The Central Archives for the History of the Jewish People (CAHJP) were established in 1939. They hold the archives of hundreds of Jewish communities, as well as of local, national and international Jewish organizations and the private collections of many outstanding Jewish personalities. The Archives now hold the most extensive collection of documents, pinkassim (registers) and other records of Jewish history from the Middle Ages to the present day."
The holdings of the CAHJP can be browsed in a number of ways:
Online finding aids are available for many (but not all) archival collections in PDF-format.
Some guides of interest:
- Polish Sources at the Central Archives for the History of the Jewish People – a digital updated version of the 2004 printed guide (16th - 20th Century)