Use NUsearch to identify books that the library has, as well as journal titles, videos, maps, and other more.
In NUsearch, you can search for what is in Northwestern Libraries' collections.
Tips on searching:
WorldCat is a place you can identify books that NU might not have. Ebook records within WorldCat will not necessarily take you to the full-text unfortunately, but this may be way to find additional literature on your topic.