In Rare Books and Manuscripts collection are included all printed editions (books, small prints, periodicals, maps, graphic editions) what are issued in Latvian language by 1850, in Russian by 1800, in other foreign languages by 1700, as well as editions printed after determined border years with special rarity properties (prohibited and persecuted editions, first editions of classic works, luxury editions and poligraphicaly interesting printings, the copies with remarks of authors and famous persons, etc.). In Manuscripts collection are acquired culturally important manuscripts, letters, photos, and other materials from personal archives.
NLL oldest and most valuable collection of printed materials was specially separated from the rest collection in 1951. Over the time it was supplemented by purchases and donations, mostly from individuals. Currently, in Rare Books and Manuscripts Department are stored more than 54 thousand units of different types of printed and written works.
The base of National book publishing is formed by oldest Latvian printings, starting with the oldest – church manual from 1586/87 and ending with stories translated by Ansis Leitāns, calendars of the 19th century, advice books for practical life, small individual sheets with popular songs, laws proclaimed by the state, and other texts. For research of Latvian cultural history there are important books in foreign languages printed in Latvia up to 1830 – ancient prints in Polish, German and Latin.
Special group is formed by printings on Latvia. In one of them – "Kosmogrāfija" by S. Minsters (Basel, 1550) can be found the oldest text in Latvian language what is known so far – Lord's Prayer of J. Hāzentēters. Old prints collection includes 63 incunabula (books published before 1500). They arrived in State storage mostly from private and institutional libraries abandoned during the First World War, the abandoned private and institutional libraries. The oldest incunabula – printed by the follower of Johann Gutenberg, typographer of Mainz, P. Šēfers in 1466 (?) – a book by Heinrich Herpf "Spiegel der Volkommenheit" (Mirror of completeness). Within incunabula should be mentioned also editions which are well known for researchers, such as editions of the Bible, issued by Nuremberg printer A. Kobergers, in Latin and German (1478 and 1483), and others.
The Rare Books collection stores also 287 paleotypes (editions from 1501-1550), including collections of 16th century typographers – Plantēns, Elzevīrs, Paris Royal printing-house and book collections of other companies.
The Rare Books collection has also important monuments of Russian book science. Collection has also newer and very new books with different characteristics of rarity: editions what earlier were prohibited by censorship, for example, one of remaining editions of Baumaņu Kārlis song collection "Līgo" (1874) (after the Russian censorship authorities burnedalmost all copies of the edition), contrafaction of time when Latgalian prints were prohibited, the first editions of the greatest persons of the world (J.W. Goethe, I. Kant, A. Pushkin, etc.).
In Rare Books department there is formed also collection of books printed in the Latvian exile refugee camps up to 1950. Manuscripts collection currently has more than 400 personal stocks and collections – published and unpublished essays, literary manuscripts, letters, photos, etc.