Rare Maisonette on East 57th Street This elegant duplex offers the scale and privacy of a townhouse, married with the ease and services of a distinguished Sutton Place cooperative.  The ground floor is beautifully proportioned. A welcoming foyer opens to a sweeping 25-foot living room, with high ceilings, oversized windows, and sun that pours in throughout the day. The adjoining dining room is ideal for entertaining, and connects directly to a spectacular eat-in kitchen. Designed for both daily living and festive gatherings, the kitchen offers a six-burner range, Sub-Zero refrigerator, abundant counter space, a washer/dryer, and a cheerful breakfast bay with windows.  The centerpiece of the home is its dramatic curved staircase, an architectural gesture as striking as it is graceful, which rises to the private quarters above. Its arc creates a natural alcove below, perfectly suited for seating or display, and evokes the quiet glamour of another era.  Upstairs, a generous landing serves as a true private foyer, anchored by two walk-in closets. Three well-scaled bedrooms and two full baths complete the level. The primary suite is king-sized, with south-facing windows and ample storage, while a versatile library/bedroom with elevator access offers a flexible retreat for work, study, or guests. The final bedroom, also south-facing, has great built-ins and is spacious at 11'x15'.    Designed by George and Edward Blum, the building itself is a classic of prewar architecture. A newly renovated lobby honors the grace of its 1920s origins while introducing modern sophistication. Residents enjoy a full suite of amenities, including a gym, bike room, storage, and a panoramic roof deck with sweeping city views. The cooperative is pet-friendly, and permits pieds-à-terres. A 2% flip tax is payable by the purchaser.  The location is equally enviable: the peaceful elegance of East 57th Street just off Sutton Place, moments from Trader Joe's, Whole Foods, and a collection of beloved neighborhood restaurants ranging from French bistro to Italian trattoria. Easy access to the FDR Drive and 59th Street Bridge makes this maisonette as practical as it is enchanting.   PRICED AT UNDER $750/SF, THIS MAGNIFICENT MAISONETTE IS READY FOR YOUR PERSONALIZATION.