Bancroft Library, originally built in 1949 and housed in the Doe Annex, is a historical archive of irreplaceable books, manuscripts, papers and other documents worth $1 billion. The collection includes Mark Twain papers, ancient Egyptian papyrus fragments, 15th century books and four Shakespeare folios. Degenkolb developed a retrofit scheme for the Bancroft Library, using a seismic strengthening approach that protects the contents of the space, as well as its occupants. Renovation of the interior structure increased usable space and included thoughtful placement of a lateral force resisting system. The retrofit removed interior floors, poured new foundations and reinforced sheer-walls from the basement to the roof. A state-of-the-art HVAC system now maintains precise temperature and humidity to preserve the manuscripts. A security system with 250 closed-circuit cameras and motion sensors protects the valuable volumes. In addition to practical improvements, the renovation recreated the Beaux-Arts rotunda with marble and onyx floors, bronze doors and gold-leaf medallions—a fitting bit of opulence for the library that mirrors the richness of its collection.