“Building ghosts” are the idiosyncratic remnants or imprints of demolished buildings, left behind on the sides of neighboring structures. Mostly seen in older Northeastern cities with rowhomes or party-wall adjacencies, they can reveal remarkable things, such as an old staircase going up the side of a building or plaster traces left by a set of shelves in an attic gable. As history in our changing cities is erased and remade, these ghosts can be ephemeral or enduring. They can be quickly revealed and replaced in a neighborhood seeing rapid change or unveiled and never re-covered in a neighborhood that has not seen new construction in a long time. Building Ghosts features more than 100 striking contemporary color photographs and a deeply researched narrative about Philadelphia’s buildings, neighborhoods, and the ghosts that reveal new truths and provocations about the changing city. The text and images in this lavish volume illuminate these lost buildings and found ghosts. Building Ghosts is an invitation to see the city differently, with the past clinging visibly to the present.