In the article is given the analysis of the place and destiny of the ruler of Montenegro and outstanding writer of XIX Peter Negosh’s rich collection of books. This collection became the basis for creating the national Library of Montenegro. In this connection close ties between the Cetinje library and the Serbian National Library were marked. Tragic historical circumstances prevented from keeping this library intact. Making the bibliography of this collection and the other books of that epoch is a complex problem for researchers. The solving of this problem will help to create whole bibliography of the works of Negosh.