The article attempts to present the functioning of the Gdansk Library under the patronage of the Polish Academy of Sciences. As of 1 January 1955, the scientific department of the Municipal Library in Gdansk was taken over by the Polish Academy of Sciences, and the thus established separate institution received new statutes regulating the activity of the Library and the scope of the development of its collections. Until the four-hundredth anniversary of the Gdansk Library (the establishment of Bibliotheca Senatus Gedanensis), descriptions of the history of the Gdansk PAS Library were mainly based on reports drawn up by the heads of the institution. It is on their basis that one may trace the difficult space and storage and warehouse conditions in which employees of the Library carried out their statutory tasks, with the constantly growing collections and the increasing load of services. The paper also reports the scientific works of employees of the Library as well as the editorial activity of the institution, including works documenting the collections of the Library. An important way of familiarising the general public with knowledge on the Gdansk Library and its collections was through exhibitions and displays organized by employees of the information and special collections departments.