As you walk through the main center door of the Science and Business Reading Room, you see the Book Service Desk straight ahead. Because the Library’s books stacks are closed to the public, this is where researchers turn in paper call slips to retrieve items from the General Collections and pick up delivered items. Thousands of call slip requests are received daily at Book Service Desks throughout the Library. As of May 2009, researchers were offered an alternative to paper call slips with a new Automated Call Slip (ACS) feature. Eventually, the use of ACS will eliminate the need for paper call slips.