a "Repertorium" is a sort of table of contents/directory for archived files, another German word is "Findbuch". This book gives you a hint on the files that once existed in the city of Glogau on the Jewish part of the city. The documents themselves may not have survived.
The handwriting seems to be from the time indicated, not earlier, yet the first few pages have a special "twist"in the handwriting, maybe the the clerk was brought up/used to writing Polish?
Regards from Germany
Corinna Wöhrl, Hoisdorf