Use ILL to obtain library resources not available at NU. Visit other libraries in person or use their catalogs.
The "Search Catalogs from Other Libraries"  link takes you to a listing of various catalog search systems.
Once you have found your desired materials, visit the Interlibrary Loan  office to make your request. This service is of interest to those who are studying at Northwestern University but require materials not currently held by the Library.
If you wish to visit other libraries, "Researching at Other Libraries"  provides information on obtaining InfoPasses and Letters of Introduction, which allow access to other libraries. It also includes information on the reciprocal borrowing programs at the University of Chicago and Loyola University of Chicago, as well as information on visiting other CIC (Big Ten) libraries.