Once you have found a book that you want in the classic catalog or in Summon, click on the title. That will bring you to the record for that item. The record will tell you which collection it belongs to. Most of the general collection items are located downstairs, while the rest is located in storage or in closed stacks. To find out how to request these items, click here: http://usnwc.libguides.com/c.php?g=38962&p=247345. The Brown and Levy collections are located upstairs near the study rooms and copy machine room. If you need assistance locating an item consult the floor plan (http://usnwc.libguides.com/content.php?pid=229789&sid=1900933) or ask a librarian for assistance.
Be sure to check the book's status, as well. The record will tell you if an item should be in the library or if it is checked out, on reserve, or missing.
