The notion of 'race' was central to the thinking about and administration of Aboriginal affairs in the 1930s, but its meaning was fluid. In many respects Auber Octavius Neville, senior bureaucrat in Western Australia from 1915-1940 and a national figure in Aboriginal affairs during that period, was emblematic of the race thinking of the period. This study looks at the Western Australian Moseley Royal Commission of 1934, the Western Australian Parliamentary debates and legislation of 1929 and 1936, the Canberra Conference of Commonwealth and State Aboriginal Authorities in 1937, and Neville's 1947 book, Australia's Coloured Minority - for their exemplification of race thinking. Basic incompatibilities and inconsistencies, as evidenced in Neville's thinking and action across his career, were common in the period. Neville's central administrative desire was to force biological absorption to its ultimate conclusion - the 'Destiny' of Aborigines of the part descent was to be absorbed biologically into the white community. He used scientific support to 'prove' the 'safety' of this strategy. The central premise of Neville's race thinking, however, was that some form of racial essentialism would always negatively impact upon the 'absorption' of Aborigines into white Australia. Other major figures differed with Neville over the suitability of absorption, notably Queensland Chief Protector, J. W. Bleakley, but still believed in some essential 'Aboriginal-ness'. The thesis also traces Neville's attempts to dominate Aboriginal affairs both in the construction of the 'problem' and in proclaiming solutions. Neville was absolutely certain that his solution was the only way forward. This certainty, when added to the inconsistent notions of race that informed his conceptualisation of the 'problem', produced policies and practices of insurmountable internal contradictions that have profoundly affected generations of Aborigines.