Mari Lending, professor in architectural theory and history, department of form, theory, and history, Oslo School of Architecture and Design, and founding member, Oslo Centre for Critical Architectural Studies (OCCAS). Artist Rachel Whiteread has made casts and drawings for more than 30 years in an effort to define the space between positives and negatives, public and private, manufactured and hand-made objects—always with concision, intelligence, beauty, and power. At the National Gallery of Art, an unprecedented and comprehensive survey exhibition of Whiteread’s celebrated career introduces a new generation of audiences to her work, which addresses how we live. In this keynote address for the symposium held on October 26, 2018, in conjunction with the exhibition, Mari Lending links cast sculptures by Whiteread with 19th^-century plaster monuments in theorizing “ghost structures,” which always refer to places and things absent, lost, or distant. She describes how Whiteread’s work—once briefly installed in the Cast Courts of the Victoria and Albert Museum in London—invites us to look again at lost objects and to see them anew. Cast representations, Lending says, are “complex and productive rather than simply reproductive.”