Oak Street is an off-campus facility where library materials are stored as well as restored. Books that do not get checked out often or are in fragile condition have a high-density, climate controlled home there. The Preservation and Conservation departments are located there as well.
When searching for an item in the catalog you may notice the item's location is stated as 'Oak Street Facility'. While Oak Street is not open to the public, items can easily be requested online and delivered to any library on campus for pick up. The building is just block from campus, and items are delivered twice daily during the week.
For more information visit: http://www.library.illinois.edu/circ/oak/index.html