Nazi looted property in the Potsdam University Library? The founding date of 1991 of the associated university would actually only allow the conclusion to answer this question with "No". Nevertheless, books suspected of having been confiscated between 1933 and 1945 were found here. A project funded by the German Lost Art Foundation then examined more than 6,000 books from the Jewish book collection. This publication looks back on the genesis of this collection, explains the individual steps of the provenance research, and shows its results with selected examples, illustrating, as it were, the wide range of challenges that had to be overcome.