manuscripts was in the possession of the Rebbe of every generation. In earlier generations—at the end of 18th century and in the early 19th century—this collection was relatively small. Little remains of the original collections, for almost all books and manuscripts were either destroyed in the frequent fires plaguing small towns in those days or were lost in various other upheavals and crisis situations over the generations. The bulk of the existing collection began to form in the third generation of Chabad—during the mid-19th century—and progressively expanded over time to become one of the world's most prominent Judaic libraries. Most of the collections of the first and second Chabad Rebbe's were lost or destroyed. During Chabad's third generation, under Rabbi Menachem Mendel Schneersohn (1789–1866), known for his major Talmudic-Halachic work, Tzemach Tzedek'', a more substantial collection took form. It became the nucleus of the central Chabad collection, which continued to grow during the following generations. The library is divided into three main sections: The Lubavitch Collection, The Collection of Rabbi Yosef Yitzchak Schneersohn, and The Collection of Rabbi Menachem Mendel Schneerson. The Lubavitch/Schneerson Collection The Lubavitch/Schneerson Collection consists of about 12,000 books and 50,000 religious documents and manuscripts from, and which belonged to, the first Chabad Rebbes starting with Rabbi Schneur Zalman, until Rabbi Sholom Dovber Schneersohn. In fall, 1915, as German forces approached, Rabbi Sholom Dovber and his family were forced to leave Lubavitch. He moved to Rostov, in south Russia. He sent most of his collection to Moscow for safekeeping, planning to retrieve it after the war. In 1920, however, he died in Rostov, before the end of the Russian civil war that followed World War I. As peace gradually returned to the land, his son and successor Rabbi Yosef Yitzchak finally had an opportunity to request the return of the collection. The new Soviet regime, however, nationalized the warehouse and gave the Lubavitch Collection to the Russian State Library. Only about 100 of the collections volumes had accompanied Rabbi Shalom Dovber and Rabbi Yosef Yitzchak to Rostov—for study or because of sentimental value—and these accompanied Rabbi Yosef Yitzchak on all his later wanderings, to Leningrad, Riga, Warsaw, Otwock, and Brooklyn. Today they are held in a special bookcase in the Chabad Library. During the years following, Rabbi Yosef Yitzchak attempted through various means to seek the release of his original library, but was unsuccessful. The Collection of