The links below will lead you to other kinds of books, listed in the Library Search Catalog, that on various aspects of learning German:

Beolingus is a good onlne German-Englsh dictionary.
The call number range for printed German dictionaries and other language books begins at PF3001. There are many non-circulating dictionaries in the Reference Collection. For volumes which you can check out, try the same call number area on the 7th floor.
The twelve-volume Duden series of word books is worthy of note:
We have many additional dictionaries. Here are links to listings in the Library Search Catalog:
We have a many books on German grammar and usage, mostly in the PF3111 call number range. Here are a couple of sample titles:
Here's a link to search results in the Library Search Catalog for many additional books on German grammar, mostly in the PC 3100+ call number area on the 7th floor.