ENThe Martynas Mažvydas National Library of Lithuania holds c. 300 thousand manuscripts from 14th to 21st centuries regarding Lithuanian history, culture and science, as well as the social phenomena and events taking place in this country. The collection is stored in 237 smaller or bigger groups (fonds): personal data and collective files, regarding church institutions, editorial offices, courts, societies, organisations as well as in already created collections in the Department of Rare Books and Manuscripts. They contain 15419th—2ist-century personal data archives regarding Lithuanian writers, scientists, artists, cultural activists residing on the territory of Lithuania or abroad. The manuscripts include c. 200 thousand Jewish documents. The article presents some historical information on the background of the establishment of the Department of Manuscripts and the origins of manuscripts fonds accumulated in the Library. The content of the most interesting and precious, as well as the newest, recently created fonds is discussed. Some information on the character of arrangement and sharing of the collections is also given. key words: manuscripts, Jewish documents, personal data archives, purchasing documents and donations, National Library. [From the publication]