Introducing the penthouse at 45 East 66th Street - an exquisite private modern duplex showcasing spectacular outdoor space! This remarkable residence boasts 10 rooms, four bedrooms, four-and-a-half baths, a library/den, and a laundry room, offering an unrivaled standard of luxurious living. Encompassing approximately 4,020 sq. ft. of interior space and an expansive 3,455 sq. ft. of exterior space, this penthouse delivers an exceptional blend of indoor and outdoor living. Upon entering the private elevator landing, there is an abundance of natural light that fills this home with floor-to-ceiling windows and a huge skylight. The dining area and windowed eat-in kitchen are a culinary masterpiece, boasting four-inch-thick marble countertops, meticulously crafted Arclinea copper cabinetry and drawers that effortlessly combine style and functionality, and a suite of top-of-the-line appliances including a Gaggenau cooktop with oven and vented canopy, along with a Miele convection oven. The main floor also offers a peaceful sanctuary with a workstation lounge, a versatile media room/den, and three lavishly appointed bedrooms. Ascend upstairs to discover the primary bedroom suite, which boasts serene vistas, additional outdoor space, and a spa-like bathroom adorned in Black Onyx. Upgraded windows throughout, private water pumps, and an enhanced electric power supply add convenience and reliability, elevating the living experience. This extraordinary duplex penthouse is a true gem located in one of the Upper East Side's most prime pre-war co-ops. Don't miss this opportunity to make this remarkable residence your own.