The property for this new single-family residence is uniquely situated along the natural and city-mapped ridgeline above Larkspur, a steep and heavily wooded hillside with heritage-status trees and unobstructed views of Mount Tamalpais and the San Francisco Bay. In working with the local planning agency, we sought an appropriate response to preserve the ridge by minimizing the home’s presence. While investigating the relationship between the new building and its context, we devised a sensitive and responsible design: The key was not to build on top of the hill, but rather to build into the hill, with the main volume tucked into the earth and threaded through the existing oak trees on site. To limit the building height across the ridge, the lower two levels of the building are cut partially into the slope forming a grounded plinth. This plinth houses the garage, bedrooms and private functions of the house. On top of this base sits the pavilion, housing the public functions of kitchen, dining, and living, completely open and sheltered under an elongated roof. The roof springs outward, based on a solid core, with no shear walls. Under this floating roofline, an array of sliding glass panels can retract completely into the core. What remains is almost nothing: a pool patio with a shade canopy. Mirror panels on the core further veil the building. When the house is in use, there is almost no house. The idea was to make a building disappear into the landscape. The façade was composed by layering operable transparent, translucent, and perforated screens for varied levels of day lighting, reducing the demand for electrical lighting. Additionally, the whole third floor can open up for natural ventilation or completely shut with a high performance window system to hold heat. This completely omits any need for a mechanical cooling system.