This elegant and refined 11-room duplex has been beautifully renovated and situated within one of Park Avenue's most coveted prewar cooperatives in the vibrant heart of Manhattan's Upper East Side. Nestled within the historical 840 Park Avenue, a grand 12-story limestone edifice meticulously crafted by George and Edward Blum in 1914.A spacious gallery welcomes you into the entertainment spaces, each adorned with floor-to-ceiling French doors and windows that gracefully open onto charming Juliette balconies. A generously sized, sunlit living room takes center stage, boasting an inviting wood-burning fireplace. This grand living area gazes over picturesque Park Avenue from the east and south, creating a wealth of seating options for gatherings. The formal dining room overlooks a tranquil, tree-lined street to the south, offering an exquisite setting for hosting guests. A handsomely paneled library or den features a cozy wood-burning fireplace, bespoke bookshelves, and ample storage space. The chef's eat-in kitchen has been meticulously updated with top-of-the-line appliances, including double Sub-Zero refrigerators with dual freezer drawers, abundant custom cabinetry for your finest china, silver, crystal, and glassware, wine storage, an A/V closet, a windowed pantry, and a separate laundry room with washer and dryer. A convenient powder room is located near the entryway, rounding out this level. Ascend to the bedroom level, where a magnificent primary bedroom suite beckons with abundant southern light, a wood-burning fireplace, two separate dressing rooms, and an expansive marble en-suite bathroom featuring double sinks, a separate windowed shower, tub, and water closet. The upper level further comprises a second corner bedroom with a wood-burning fireplace and an en-suite bathroom, a third bedroom facing Park Avenue with its own en-suite bathroom, and a fourth bedroom also equipped with an en-suite bathroom. Throughout this exceptional residence, custom-fitted closets and storage solutions abound, while central air conditioning, hardwood floors, and ceilings as high as 10 feet enhance the sense of space and comfort. This remarkable home provides an oasis of tranquility for gracious living and grand entertaining. 840 Park Avenue offers an unparalleled level of service, privacy, and security, with a 24-hour doorman, attentive porters, and a resident manager. The building permits pets and pieds- -terre, and a storage cage transfers with the apartment. A 2.5% flip tax is to be paid by the buyer, and the building now allows for 50% financing.