As a university library the Zentralbibliothek collects academic literature on all the subjects taught at the University of Zurich, with a special focus on the liberal arts and social sciences. As the Turicensia guardian it collects all publications published by Zurich-based publishing houses, all works of Zurich-based authors and all literature on Zurich itself. As city and cantonal library the ZB also offers a wide selection of popular literature – from travel guides and self-help books to biographies, crime thrillers, DVDs and sound recordings. The ZB's five Special Collections – Graphics, Manuscripts, Maps, Music and Old Prints – boast a wealth of historical and current archives, bequests, image and sound documents. As the oldest cultural institution in Zurich, the Zentralbibliothek organises regular exhibitions to present its collections and the topics on which they focus to a broader public. It offers guided tours and training courses to teach key information skills to students at all Zurich universities, high school students and the wider public. The ZB is also very involved in training and continuing education in the library sciences, and offers a masters degree in library and information sciences at the University of Zurich.