GBV is the Common Library Network of the German Federal States Bremen, Hamburg, Mecklenburg-Vorpommern, Niedersachsen, Sachsen-Anhalt, Schleswig-Holstein and Thüringen. The head office of the GBV (VZG) is situated in Göttingen.
The GBV has established a virtual library in form of the GBV Union Catalogue (GVK) combining the resources of all participating libraries and making them easily accessible to the public.