On the corridor leading west, and running along the 40th Street end of the building, are workrooms, open only to visitors having business engagements. These rooms are the office of the Order Division (No. 204) and of the Cataloguing and Accessions Divisions (No. 200 and No. 201).
SOUTH COURT
THIRD FLOOR
The most important room on the third floor and, indeed, the centre of activity of the entire Reference Department of the Library, is the Main Reading Room, approached through the Public Catalogue Room. The latter opens from the western side of the corridor at the head of the staircases.
Public Catalogue Room. This room (No. 315) contains the catalogue of the books in the Reference Department of the Library,—that is, the books available to readers in the Main Reading Room and in the special reading rooms of the Central Building. It is a dictionary catalogue, on cards, in which the books are entered by author, by subject, and by title, when the title is distinctive. The catalogue is in trays arranged in alphabetical order, beginning on the northwest wall of the room and running to the right. At the end of this catalogue, and on the southern side of the room, is an author catalogue of the books in the Central Circulation Branch and Central Children's Room, Rooms 78 and 80, in the basement. At the end of this second catalogue and separated from it by a public telephone, is a catalogue of the books in the Library of Congress for which printed catalogue cards have been issued.
NORTHWEST CORNER