The role of the National Library brought with it the charge to gather and house forevermore any work produced by the Jewish people in its own and foreign tongues, and all written records or documents of Jewish history, whether concerning the Jewish people itself or its relations with other nations.

The Jewish cultural legacy was not, however, the Library's sole focus. The University was established so that "the windows of this edifice are open to the four corners of the world, that the fairest fruit produced by man's creative spirit in every land and every age may enter (Chaim Nachman Bialik). Thus, the Library's mandate was also to collect and preserve the legacies of other cultures.

The treasures of the Jewish National and University Library are indeed priceless: manuscripts of the Bible; works written by the greatest Jewish thinkers in their own hands; manuscripts of eminent scholars and scientists, both Jewish and non-Jewish; incunabula and early editions; works of art; and more.