Books in constant demand by readers, especially heavily used textbooks, are removed from the open shelves and placed in a controlled access collection in the Reservation Book Room on the ground floor of the main building. Special materials from the Research Library required for undergraduate reading are also kept in the reserve for use under supervision. Academic staff must send in advance to the Library, copies of all reading lists for students, and particularly titles of works, which are specially recommended for the attention of classes. This enables the Library to obtain those materials, which are not already in stock. The course and the desired duration of reservation must be indicated, so that reserved books may not be kept indefinitely out of circulation to other Library users. An indication of the number of students requiring the books helps in determining the number of extra copies to be provided. Students themselves are welcome to recommend books to be put on reserve. Finally, it is important that teaching staff confer periodically with the Circulation Librarian about this service.