The Rare Book and Special Collections Reading Room in general houses materials published before 1801. Exceptions to this rule can be made based on an item's scarcity, cultural impact or provenance. The reading room has strong holdings of Russian content in large part due to two landmark acquisitions: the Yudin collection in 1906 and the Russian Imperial Collection in the 1930s and 40s.
The Yudin collection consists of the private library of Gennadii Vasil'evich Yudin, a Russian merchant and bibliophile. In his lifetime, Yudin compiled one of the greatest and most diverse private libraries in 19th-century Russia, containing at its peak over 80,000 items. With the purchase of the Yudin collection in 1906, the Library of Congress became a leading repository of Russian books, newspapers, journals and other materials. Over time, items in the Yudin collection were dispersed throughout the Library of Congress based on format (e.g. maps to the Geography and Maps Reading Room, legal documents to the Law Library, etc.). As a result, the Rare Book and Special Collections Reading Room has a wide selection of Russian books and journals from the eighteenth century, many of which come from the Yudin collection. In addition, due to the relatively late development of mass publishing in Russia and the small print runs of Russian books and journals in the early nineteenth century, the Rare Book and Special Collections Reading Room holds select Russian materials from the Yudin collection published before 1850. It is worth reiterating that the Yudin collection in its entirety is not held in the Rare Book and Special Collections Reading Room. Yudin collection items can also be found in the General Collections of the Library of Congress as well as in other reading rooms. To find out more about the Yudin collection as well as tips on how to find collection items at the Library of Congress, see this guide:
To explore the Library of Congress' holdings of 18th-century Russian publications, see these guides:
Eighteenth century Russian publications in the Library of Congress : a catalog by 
Russian 18th-century Periodicals: a resource guideThe Russian Imperial Collection is comprised of about 2,800 volumes of books and periodicals which previously belonged to the Romanov family or one of the imperial palaces. The collection was acquired by the Library of Congress over several installments during the 1930s and 40s, mainly through the bookseller, Israel Perlstein. The subjects of literature, law, religion and military science are especially well represented in the collection with materials in Russian, French, German, English and Danish. Although the identification of Russian Imperial Collection items in the online catalog is ongoing (and thus not comprehensive), you can explore the materials that have been organized under the "Russian Imperial Collection" subject heading here:
It should be noted that significant portions of the Russian Imperial Collection are also held in the Performing Arts Reading Room and the Law Library.
Last, the Rare Book and Special Collections Reading Room has rich holdings of religious literature, especially Bibles, from Russia and other Slavic countries. These works are published in Old Church Slavic, the liturgical language of the Russian Orthodox Church. The crown jewel of the collection is a copy of Apostol', the first dated printed book from Russia published in 1564. To explore more titles in Old Church Slavic at the Library of Congress, see this guide:
The unique materials of the Rare Book and Special Collections Division, now totaling over 1 million items, include books, broadsides, pamphlets, theater playbills, prints, posters, photographs, and medieval and Renaissance manuscripts. At the center is Thomas Jefferson's book collection, which was sold to Congress in 1815. The Rare Book & Special Collections Reading Room is modeled after Philadelphia's Independence Hall. This room is home to the divisional catalogs, reference collection, and reference staff. Collections are stored in temperature and humidity controlled vaults.
