A rare architectural offering this one-of-a-kind 1956 Eichler X-100 prototype by Jones & Emmons represents a pivotal moment in mid-century modern design. Commissioned by Joe Eichler, the home showcases six exposed steel I-beams, eliminating interior load-bearing walls and creating a dramatic open, light-filled environment with seamless indoor-outdoor flow. Thoughtfully restored while honoring its original vision, recent updates include fresh interior/exterior paint, recoated foam roof, refinished vinyl and concrete floors, updated radiant heating, curated furnishings, and refreshed landscaping inspired by original landscape architect Douglas Baylis. The home is organized around two private garden atriums with in-ground planting beds, while 32 feet of skylights flood the interiors with natural light. Signature materials, steel, glass, and Formica, highlight the home's authentic modernist character. Built-ins and kitchen elements are fully integrated into the architecture. Debuted in 1956, the X-100 gained national attention and influenced generations of modern residential design. Shaped CA Modernism. Listed on the National Register of Historic Places, this is a true collector-grade property ideal for design enthusiasts, historians, and those seeking a singular living experience.