Sir George Grey (1812-1898) served as Governor of South Australia, of New Zealand twice, and of the Cape Colony. This thesis explains his policy for the first time for a history of the political ideas of colonization. Grey introduced the policy of racial amalgamation to settler colonies after the 1837 Report of the Select Committee into Aboriginal Affairs, that had advised the policy of segregation as had been North American policy under Sir William Johnson. This thesis demonstrates that Grey was a Liberal Anglican who had adopted neo-Harringtonian thought, and who introduced Jeffersonian native policy into British native policy. He practised the strategic theory of Antoine-Henri Jomini, applying it to native policy. Grey captured the monarchical constitution of the empire for what had been a settler policy of dissent to the segregation of indigenes that dated back to Tudor Ireland and early Viginia. Grey's distinctive intellectual practices were ethnograpical research and speculation, for which he enjoyed an international reputation, and the constitutional design of settler colonies, an activity he came to totally identify with. The thesis concentrates on his first New Zealand governorship (1845-53) and upon the resumption of his second New Zealand governorship (1861-68) because it was in that colony he first fully practised his native policy and participated in constitutional design, and into which he brought about a crisis of indigenous amalgamation on the eve of the Waikato War in 1863, having introduced full responsible government.