This magnificent 15-room terraced duplex apartment is located on the 14th and 15th floors of one of Manhattan's most distinguished Park Avenue prewar cooperatives at the corner of 73rd Street.   Grand proportions, soaring ceilings, floor to ceiling windows, original herringbone floors and, classic moldings enhance the graceful layout of the home.  Incorporating 28 windows spanning three exposures, glorious light and charming city views abound.  A stately 14' x 13' gallery leads to a dramatic 29' corner living room overlooking Park Avenue with traditional moldings and a wood burning fireplace.  The adjacent 20' library has attractive built-ins and a Park Avenue view.  Accessed off the reception hall, the corner, formal dining room offers an elegant setting for entertaining.  The windowed kitchen has a large breakfast area and, a butler's pantry.  A 17' family room could easily serve as an additional bedroom.  The upper level includes five to six bedrooms, each with a full bath en suite and two terraces.  There are also two staff rooms, a staff bath and a separate laundry room.  Built by the legendary Rosario Candela in 1930, this 18-story Georgian-style building is considered to be among the city's finest cooperative apartment houses.  Residents of this building enjoy the utmost in service, privacy and security.  Amenities include a state-of-the-art fitness center, storage facilities and wine cellar.