=Business Offices.= The rooms opening from the corridor running south from the main staircase are mostly business offices, devoted to the administration of the Library. They are of little interest to sightseers, but are open to any persons who have occasion to visit them. They include, on the front of the building, a lecture room (No. 213), the office of the Director of the Library (No. 210), and the meeting room of the Board of Trustees (No. 205). On the inner or western side of the corridor are: a study (No. 214), the office of the Editor of Publications (No. 212), and of the Reference Librarian (No. 211). The Trustees' Room may be seen on special application at the Director's office. Over the mantelpiece in this room is the inscription: THE CITY OF NEW YORK HAS ERECTED THIS BUILDING FOR THE FREE USE OF ALL THE PEOPLE MCMX I LOOK TO THE DIFFUSION OF LIGHT AND EDUCATION AS THE RESOURCE MOST TO BE RELIED ON FOR AMELIORATING THE CONDITION PROMOTING THE VIRTUE AND ADVANCING THE HAPPINESS OF MAN THOMAS JEFFERSON [Illustration: MALL BEHIND LIBRARY] 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). [Illustration: 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. [Illustration: NORTHWEST CORNER] Near the entrance to the Public Catalogue Room, and at the right, is a bronze tablet: