Single-level, authentic, Mid-Century Modern home in the coveted flats of Belvedere. Welcome to 2 Tamalpais Avenue, a rare architectural offering designed by acclaimed architect Charles Warren Callister. This iconic residence showcases a preserved original floor plan and remains in semi-original condition. Set on a mostly level lot, the property features a pool and exceptional potential for expansion. Included remodel plans by known Bay Area Architect Lev Weisbach, Weisbach Architecture Design, along with design approval for a detached ADU offer a compelling vision for future development. Comprehensive supporting documentation, including geotechnical and structural reports, provides a seamless path for transformation. Ideally located just moments from downtown Tiburon, enjoy effortless access to ferries, waterfront dining, boutique shopping, local markets, and two prestigious yacht clubs. Nearby parks and the scenic Old Rail Trail invite an active, outdoor lifestyle. A rare opportunity to own an architectural gem in one of Marin County's most sought-after neighborhoods.