WorldCat is a comprehensive online catalog of library holdings. lists books, journals, maps, recordings, films, scores, and other materials located in over 6000 public, academic, corporate, school and specialized libraries all over the world. Check WorldCat for holdings of materials that are not available at Princeton University Library; these items can be requested through Interlibrary Loan or Borrow Direct. Items that are available here are usually marked with this icon: 
PRINCETON UNIV , but double check to be sure. You can use the 
icon to quickly search Main Catalog for that item; this is essential because the item might be checked out, lost, or unavailable for some other reason.
Currently there are two ways to search PUL collections - through the Main Catalog (familiar to PUL veteran users) and through the new Books+ system, as seen above in the top right box. Both systems search the exact same content but each has its own unique functionality.
Can't find a book you need? Need a book that's checked out? Need an article that's not @ Princeton?
Borrow Direct: A quick turnaround service shared between Brown, Dartmouth, Princeton, Yale, Harvard, MIT, Penn, Cornell, and Columbia. This service is for books only. For articles, essays, or books not found in the Borrow Direct network, use ILL.
Interlibrary Loan (ILL): Another borrowing service that tracks down a wide variety of material- books, articles, dissertations, etc.- from hundreds of library networks across the world.
