The small room off the entrance hall to the northwest was, according to tradition, Shirley's library, and it was used for this purpose by the Eustises.
The library retains its original closet doors and trim, dado, portions of the cornice and its wood floor. The painted floor duplicates remnants of the original, which was discovered under many coats of paint during the house’s restoration.
The fireplace surround dates to Shirley's time and is one of the only two in the house that were not replaced in the Federal period. In deliberate contrast to the French furnishings in the rest of the house, and in commemoration of William Sumner Appleton (1874 - 1947) and the other early preservationists who saved the Shirley-Eustis House, the furnishings in this room were selected to represent the colonial revival style, which formerly dominated period-room installations. The Windsor chair was made in New England, 1775 - 1785. The mahogany and pine slant-front desk is from Massachusetts, 1770-1790. On it are a mahogany shelf clock made by Aaron Willard (1757-1844) in Boston, c. 1800; a pair of bell metal candlesticks, English, 1770-1800; an English brass taper stick, c. 1800; and a silver inkstand, also English, 1780-1800.