finest and most intact houses that survives from the first half of the 1950s in NSW. The house demonstrates advanced planning and split level configuration, and demonstrates convincingly and well the characteristics of the Modern Movement residential architecture. The aesthetic value of the house is due in part to the exploitation of its structural system to provide dramatic spatial qualities and architectural form. It also provides evidence of advanced residential technology and amenity from this period, such as fluorescent and other lighting, kitchen design and surviving joinery, built in joinery items including the cabinet in the living room, which accommodated stereo equipment, and early passive sun control devices. The materials used in the house-stone, timber, brick, steel-framed windows-the built-in joinery and detailing are a consistent part of Seidler's architectural repertoire at this time and demonstrate his skill in exploiting their intrinsic textural qualities and colouring. The landscape setting, despite inadequate maintenance, demonstrates architect Harry Seidler's philosophy that the settings for his houses be naturalistic. Views from the house over the treetops to the Georges River are significant as an essential element of the design of the house in its landscape setting. The place possesses uncommon, rare or endangered aspects of the cultural or natural history of New South Wales. Thurlow House is of state significance as a rare example of a highly intact post-World War II Modern Movement house in NSW, which demonstrates advanced domestic construction and planning techniques. Although a relatively large number of Seidler's early houses have survived, many are known to have been subjected to alterations and additions which in some cases have obscured their early design and character. Thurlow House is rare at a state level as an intact example of the early architectural work of Harry Seidler. The place is important in demonstrating the principal characteristics of a class of cultural or natural places/environments in New South Wales. Thurlow House is of state significance as a fine, representative example of post-World War II Modern Movement domestic architecture in NSW. The house is representative of the early domestic architecture of Harry Seidler. It demonstrates many of the characteristics of his residential design, including planning and organisation of spaces over several levels to exploit views and provide amenity for the occupants; built-in joinery units and general standard of detailing; and exploitation of structure to achieve open planning and spatial complexity. The representative qualities of the house are