A museum-quality upper Fifth Avenue contemporary alteration of two apartments features a new steel stair with glass risers and glass rail panels. New spaces include a den / office, playroom, kitchenette, guest room and private office with dedicated bathroom. The lower level den space is isolated from the upper level with a frameless full height glass door. A new play space was created at the upper level of the apartment where new fabric-covered impact-resistant panels protected original plaster walls. Surprise and delight occurs when you enter the new contemporary sycamore detailed office suite. Interior design of this space is on par with any museum-quality corporate office design.