house design by architect Harry Seidler, who produced an important body of work in NSW, other parts of Australia and internationally. Seidler's architecture is notable for its consistent and rigorous application of Modern Movement principles. Thurlow House reflects the impact of Seidler's seminal and early Rose Seidler House on sections of the wider community. Members of the professions amongst others were attracted to Seidler's work because of its design characteristics and because of publicity generated by the architect, in part because of his significant battles with local government over advanced architectural design and aesthetics. It is a remarkably intact house that has undergone little change since it was completed in 1954, and provides evidence of the dissemination of advanced Modern Movement architectural design in NSW after World War II. The garden and grounds of Thurlow House include remnant indigenous vegetation, which was intentionally retained during the construction of the house and demonstrates Seidler's preferred philosophy that the setting for his houses should be minimal in a horticultural sense. This was uncommon for development in the early 1950s. The place has a strong or special association with a person, or group of persons, of importance of cultural or natural history of New South Wales's history. Thurlow House is of state significance for its association with internationally significant architect Harry Seidler and it is a fine example of Seidler's modernist design methodology. Seidler was the only architect working in NSW who had trained and worked under influential architects associated with the Bauhaus and brought a thorough understanding of European modernist methodology and aesthetics to NSW. The house is important in Seidler's body of work because of its particular split level configuration, whereby entry to the house is at mid-level and bedrooms are located on what equates to a mezzanine above living areas. The cantilevering of the bedrooms over the deck of the living areas is also a unique response to the constraints imposed by the site and its available views. The Thurlows are representative of the young professional social class who commissioned Seidler, demonstrating awareness of, and positive response to, advanced architectural design within sections of the general community. The place is important in demonstrating aesthetic characteristics and/or a high degree of creative or technical achievement in New South Wales. Thurlow House is of state significance as a finely designed and well-executed example of Modernist residential architecture. It is one of the