Endowed by Asa Packer in memory of his daughter, this was one of the most comprehensive libraries of its day. Its plan is a panopticon and based on that of Princeton's Chancellor Green Library, just finished by William A. Potter in 1873. Stacks radiated outward from a reading room, opening up through three floors, with wood-floored walkways serving the stacks at each level. The decorative iron railings remain, as does the open iron spiral stair and the Tiffany stained glass oculus above. By the 1920s, the library had long since exceeded its 150,000-volume capacity. Fortunately, Packer's bequest included an operating endowment four times the library's cost and a capacious addition could be built. Completed in 1929, the new wing quadrupled the available square footage and tripled stack capacity. It was designed by Visscher and Burley in a sympathetic Gothic style, although far less severe than Hutton's cold gray rotunda. Of particular note is the splendid reading room, which retains its wood paneling, heraldic fireplace, and leaded glass casement windows. A recently completed renovation by Philadelphia's MGA Partners happily emphasizes the historic features.