This transformation of a post war penthouse apartment in Boston's historic Back Bay, creates a sculpted perimeter along the south facing wall. The existing compartments of the bedrooms have been replaced with a single open living room and kitchen adjacent to the master bedroom. A pivot door to the master bedroom allows the entire perimeter to be opened. A renovated master bathroom replaces two small bathrooms, and a new bedroom and study occupies the site of the former kitchen. A second bathroom, located at the center of the apartment, borrow light from a new sky lit stairwell to the roof above. The stairs that access the roof cascade down and transform to become a bench and display area at the entrance. A White Fantasy quartzite slab creates the kitchen counters, and white lacquered millwork completes the palette. The floor is a pickled white oak which complements the palette and gives the apartment a light and airy feel.