City and State Library
Due to a cooperation between the City of Dortmund, the University Library and the AStA, students of the TU Dortmund can get a free pass to use the city library (Stadt- und Landesbibliothek) near the main station and all branch locations in different neighborhoods in Dortmund. To get the free pass, you have to present a current study certificate or your semester ticket at the library together with your ID card/passport.
Take advantage of the wide range of literature for your free time or your study. Also interesting is the big newspaper archive and the working spaces nearby the main station. The also have a big variety of non-German literature.
You can find more information here (only in German): https://www.dortmund.de/de/leben_in_dortmund/bildungwissenschaft/bibliothek/start_bibliothek/index.html