We have the complete Chronicles of Narnia written in German!
Sometimes wandering the shelves is useful. If you can find one book on a topic, others like it will be sitting on the same shelf. Be sure to look in both the Reference collection on the first floor for general helps like encyclopedias, and in the circulating collection on the second floor for books you can take with you. These numbers work for most other academic libraries as well.
PF3001-5999 German language
PF3801-3991 Old High German
PF3992-4010 Old Saxon
PF4043-4339 Middle High German
PF4514-4595 Early Modern German
PF5000-5951 Dialects. Provincialism, etc.
PF5971-5999 Slang. Argot, etc.
PT1-4897 German literature
PT1-80 Literary history and criticism
PT23-871 History of German literature
PT1501-2728 Individual authors or works
PT3701-3971 Provincial, local, colonial, etc.
PT4801-4897 Low German literature
For more in-depth information, see Library of Congress Classification Outline: Class P