This longitudinal section, created late in the design process, depicts the Library’s three principal rooms. At left is the West Room (Morgan’s study), with its low bookshelves and space for the display of artworks. At center is the Rotunda, the main hall, with its highly decorated domed ceiling and ring of pilasters. At right is the East Room, the grand space in which much of Morgan’s book collection would be prominently displayed. A dotted line traces the position of a spiral staircase that begins at the cellar level.
The doorway at the immediate center leads to the North Room, which would become the office of Morgan’s librarian, Belle da Costa Greene. The antique stone doorframe is engraved with the motto Soli Deo Honor et Gloria (Glory and honor to God alone).