Fifth Street façade, Library HallAlthough the Philosophical Society made no systematic effort to purchase books and manuscripts prior to the Revolution, materials nevertheless accumulated through exchanges with peer institutions around the world. The question of what to do with these books, however, was never formally addressed, and the slowly growing collections were housed in various locations, including, for a time, at the home of the Society's Librarian, David Rittenhouse. With the completion of Philosophical Hall in 1789, the library found a home, occupying one room or another for the next one hundred and forty-five years.

Interior of third floor addition, Philosophical Hall, ca.1940By their very nature, libraries expand, and the APS library was no exception. By the end of the nineteenth century, the steady growth of the collections had produced such a critical need for additional space that the Society decided to add a third story to Philosophical Hall in 1890. The structure they built, often called the "folly of the third story," was a dreary, windowless, box-like structure designed with minimal attention to the architectural integrity of the building or its effect on its neighbors on Independence Square. It was also sadly inadequate to meeting the library's need for space.

The collections were packed tightly into this third story addition until 1934, when the opportunity arose to move into more spacious quarters. Across Fifth Street from Philosophical Hall, occupying the east side of the street, from Chestnut to Library Streets, was a large office building built in 1887 and financed by Anthony J. Drexel. The third floor had been vacated by the Philadelphia Stock Exchange, and offered more than sufficient space for the library at the time.

Drexel building during demolitionYet this, too, provided only a temporary respite. When plans for the redevelopment of the Independence Square historic area were drafted in the 1940s, it became clear that the days of the intrusive and hulking Drexel Building were numbered. Temporary quarters were found for the library in the United States Fidelity and Guaranty Building, directly south of the Drexel Building, while the Society weighed its options. In 1952 plans were drafted to erect a new Library Hall on the site of the Drexel Building, which coincidentally had also been the site of the original Library Company of Philadelphia from 1790 until 1887.

Dedicated in November 1959, Library Hall reproduced the famous Georgian façade of the Library Company's Hall, complete with a statue of Benjamin Franklin ensconced in a niche above the doorway. The architect of the Library Company Hall, William Thornton (1761-1828), is remembered for having won the competition to design the U.S. Capitol building.

Architect's rendering of Fifth Street façade of Library Hall: By Sydney E. Martin, 1952.Built with then state-of-the-art library construction techniques and systems in mind, the Society's Library Hall has seen a number of renovations to its physical plant over the years, most recently in 1999. Undertaken with a view toward safeguarding the collections and providing a pleasant atmosphere in which to work and conduct research, these renovations help position the Library for continued growth into the twenty-first century.