The first place to start looking for books is BobCat, NYU's online catalog, which includes records for materials held in the following NYU Libraries of likely interest to those in Medieval & Renaissance Studies:
The holdings of NYU's Law Library, Medical and Dental Libraries are not listed in BobCat. Their catalogs are listed below.
The following are catalogs of other libraries at NYU and in the New York area that may be useful to those studying the Middle Ages and the Renaissance.
If you do not find a book in BobCat, and it is not convenient to visit one of the other New York area libraries listed above, the best next step is WorldCat, an international union catalog listing the holdings of more than 10,000 libraries. Beyond WorldCat, the following catalogs can be of use to those studying the Middle Ages and the Renaissance: