During the Independent State of Croatia, books and libraries were confiscated from individual Jewish persons and handed over to the National and University Library in Zagreb, but without any listing. Many of these books were seized by the Ustaše from Jews living in Croatia, while others were plundered by them from Jews who were escaping to the south from as far north as Hamburg.
In recent decades, the National and University Library in Zagreb has returned some 7,000 books to the Jewish Community of Zagreb.
However, because of the Holocaust, there are practically no librarians or other personnel in Croatia able to identify and catalog the books and manuscripts in Hebrew and other Jewish languages such as Ladino and Yiddish.
In cooperation with the Jewish Community of Zagreb and the National Library of Israel, the Claims Conference-WJRO started a pilot project to organize the cataloging of these books and the examination of markings that may help to determine the provenance of the volumes. The project may serve as a model of what to do in regard to the identification and cataloging of looted Jewish books in countries that due to the Holocaust lack the necessary personnel.
As of late spring 2017, the National Library of Israel (NLI) completed its work, having examined 6800 items for which the Jewish Community of Zagreb provided scanned images of the title and other relevant pages. Of these, 601 had a missing or illegible title page, leaving 6199 items that were matched to an NLI catalogue record or were otherwise catalogued. The Jewish Community of Zagreb provides information on these volumes online, as does the NLI catalogue.
There were 346 items that were previously unknown to the NLI, including 37 books in the Jewish Community of Zagreb collection that are not in the NLI and which were deemed as most important resulting with the NLI considering requesting a full scan of these items.
1552 books in the Jewish Community of Zagreb were bearing inscriptions or ex libris marks that provide possible information as to whom or to which institutions these 1552 Jewish books originally belonged.
In order to see the images of inscriptions or ex libris marks, please go to the following web address within the National Library of Israel catalogue: http://primo.nli.org.il/primo_library/libweb/action/search.do In the upper left corner you can switch to English. Then paste one of the bibliographic numbers in the attached list and press the search button. If you press “Details” you will get the full cataloging record, and if you then press the Hebrew term “תמונה קדמית” at the bottom of the record, you will see the image of the book with an inscription or ex libris or other marking relevant to the provenance of the volume.
Persons able to decipher the inscriptions or ex libris or other markings are requested to send the resulting information to the attention of the Claims Conference-WJRO Looted Art and Cultural Property Initiative at the following e-mail address: CroatiaBooks@claimscon.org. The information will be assembled and forwarded to the Jewish Community of Zagreb and the National Library of Israel.
 These books were in addition to and separate from those from the library of Dr. Lavoslav Šik that Dr. Šik had loaned to the National and University Library in order to avoid confiscation by the Ustaše and which, since they had been on loan, were returned to the Jewish Community of Zagreb in 1959.
 Of the 601 items that did not have or had an illegible title page, 81 had inscriptions or other markings possibly relevant to their provenance.
 Thanks are due to all who have worked on this project, in particular the following:
- Jewish Community of Zagreb: Dean Friedrich
- National Library of Israel: Aviad Stollman, Ariel Lock, Erez Elimelech
- Conference on Jewish Material Claims Against Germany/World Jewish Restitution Organization: Wesley Fisher, Max Kuba, Tony Rodriguez, Ruth Weinberger