This Upper East Side apartment was completely transformed from a traditional pre-war residence with rigidly divided rooms and functions into a more open, flexible contemporary home. A central spine seamlessly connects public and private spaces that can be opened and closed through a series of sliding and pocket doors. Built-in cabinetry permeated the entire space, from the walk-in closet to the bathrooms; dark stone and wood flow from one room to another, unifying the interior. All the mill work and furnishing reflect the clients' decidedly modern sensibility.