Set on one of Marlborough Street's most coveted blocks, this beautifully renovated top-floor duplex combines classic Back Bay character with an exceptional indoor-outdoor layout rarely found in the neighborhood. The main level offers an open, gracious flow among the living, dining and kitchen areas, framed by a front-facing bay, marble fireplace and custom built-ins. Two bedrooms are privately positioned at the rear of the residence. The primary suite features skyline views, a second marble fireplace, a walk-through closet and a renovated en suite bath. A well-proportioned second bedroom and an additional renovated full bath complete this level. Upstairs, a window-lined lounge creates a distinct second living space, complete with wet bar and powder room. Equally well-suited to entertaining, working and unwinding, the lounge opens directly onto an expansive private wraparound roof deck, thoughtfully arranged into distinct areas for dining, lounging and gathering. This seamless, same-level indoor-outdoor connection - exceptional in both scale and versatility - is a defining feature of the residence and a true rarity in Back Bay. Additional features include in-unit laundry, central HVAC, integrated lighting and audio, and dedicated storage. Offering an uncommon combination of privacy, architectural character and expansive outdoor living, this distinctive residence presents a compelling opportunity in one of Boston's most enduringly desirable neighborhoods.