This modernist gem, tucked away on Marin County’s Belvedere Island, packs a triple whammy. Not only was the home created by noted Bay Area architect William Wurster and pioneering landscape designer Thomas Church, but it’s perched on a hilltop site with panoramic vistas stretching from the San Francisco skyline to Sausalito, Mount Tamalpais, and the Golden Gate Bridge.

Completed in 1967 for California deputy attorney general Leonard M. Sperry Jr. and his wife, Rita, the property sold for only the second time in 1979 for $1.2 million. It later underwent a two-year, $5 million renovation. Now, after serving as a family retreat for almost five decades, the revamped spread has just come available through Bill Smith and Ann Aylwin of Compass as an off-market listing at $50 million. It would set a Marin County record if it sells near the asking price.

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Tucked away at the end of a secluded cul-de-sac on two contiguous parcels spanning just under an acre, the wood-sided and flat-roof structure offers eight bedrooms, nine full bathrooms, and two powder rooms in 9,170 square feet of inverted living space across three levels accessible via an elevator and a winding, skylit staircase. The main living spaces on the top floor are introduced by a limestone-clad foyer, which passes a wet bar on the way to a wood-paneled living room sporting a green marble fireplace, a retractable screen for movies and presentations, and a curving wall of windows.

A fireside family room and a formal dining room flank the kitchen, which is outfitted with an eat-in island, a glossy mosaic-tiled backsplash, and a breakfast/lounge area warmed by a fireplace, along with a separate prep kitchen and workstation. All the living spaces open to a sprawling deck running the entire length of the house.

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Six en-suite bedrooms can be found on the middle level, including an octagon-shaped primary suite with a fireplace, a private balcony, a walk-in closet, and a marble bath. Another en-suite bedroom and a one-bedroom, one-bath guest suite with a living area, kitchenette, and private deck occupy the bottom floor along with a large L-shaped recreation room with an exercise space.

In addition to numerous terraces, patios, decks, and balconies stepping down to flat grassy lawns, mature plantings, and meandering pathways, the lush grounds host a sundeck-encased pool and a sport court. There’s also an attached two-car garage and additional parking for up to 12 more vehicles.

Click here for more photos of the Marin County residence.