ENThe appearance of copyright libraries contributed greatly to the circulation and preservation of books. In Western Europe the beginnings of these libraries go back to the sixteenth century. By special acts they were entitled to receive a copy of every book published in the country. The present article is a review of the stages in the development of the copyright libraries in Lithuania since the end of the sixteenth century. The first stage was associated with the appearance of such libraries as institutions. By his decrees of 1598-1615 the Jesuit general Claudius Aquaviva founded the Jesuit College of Vilnius with a printing-house, indicating that a copy of every book published should be sent to the centre of the Society of Jesus in Rome. On 28 November 1761 Laurentius Ricci entitled the Załuski Public Library in Warsaw to receive a free copy. The publications of the Vilnius Academy printing-house also reached the Jesuit colleges of Vilnius and other cities. To a certain extent the publications of the Vilnius Orthodox fraternity of the Holy Ghost were sent as deposit copies to the fraternities of Lvov and Kiev. The second stage of the history of libraries was characterized by the extension of the functions of libraries and the enlargement of their collections in the Polish-Lithuanian Commonwealth in the middle of the eighteenth century. That process started with the 10 March 1766 decree of Stanislaus Augustus on depositing a copy of every publication in the Załuski Public Libraiy of Warsaw, the Vilnius Academy Library and in the royal library. By the same decree the Vilnius Academy Library was given the status of the public library.The third stage in the development of copyright libraries began with the dissolution of the Society of Jesus in 1773 and the establishment of the Educational Commission. On 2 November 1780 the Warsaw Seym passed a law on the expansion of public libraries. By that law all Polish printing-houses had to deposit one copy of their publications in the Załuski Public Library, while the printing-houses of the Grand Duchy of Lithuania were to send their copy to the Vilnius Academy Library. The enforcement of this law was entrusted to the Educational Commission. The fact that this law was adopted by the Seym and not by the sovereign and that its purpose was the enlargement of collections reflected its democratic character. However, the regional principle of its implementation is to be regretted. After the last partition of the Polish-Lithuanian Commonwealth in 1795 and after the set-up of the Educational Commission in Lithuania, the same principles of depositing copies in the libraries were observed. In its session of 18/29 November (Old/New Style) 1799 it passed a corresponding decision. In 1802 an educational reform was carried out in the Russian Empire, and Lithuania had obey to new laws. The University of Vilnius was granted a right to control and censor the activities of all printing-houses of the Vilnius educational district.