Both a book and a sculptural object, Absence is a memorial to the twin towers of the World Trade Center. Yoon, an architect and designer who is currently an Assistant Professor of Architecture at the Massachusetts Institute of Technology, chose not to produce a traditional design proposal for the World Trade Center Memorial Competition. Instead she created a non-architectural, non site-specific space of remembrance: a portable personal memorial in the form of book.At almost two pounds, Absence has a considerable physical presence, but it is in every way the ghost of a presence, and it is this ghostliness that gives it its particular emotional weight. A solid white block of thick stock cardboard pages, the books only "text" consists of one pinhole and two identical squares die-cut into each of its one-hundred-and-twenty pages one for each story of the towers including the antenna mast. These removed elements lead the reader floor by floor through the missing buildings towards the final page where the footprint of the entire site of the World Trade Center is die-cut into a delicate lattice of absent structures.