Racial differences in intelligence, personality, and behavior have been discussed since ancient times. In the second century A.D. the Greek physician Galen wrote that black Africans are less intelligent than Europeans. In the Middle Ages a number of Persian and Arabic writers took the same view, and in the thirteenth century the Persian geographer Nasir al-Din Tusi went to far as to assert that black Africans were less intelligent than apes. The first to attempt to quantify race differences in intelligence was Sir Francis Galton in his *Hereditary Genius* (1869). He estimated the intelligence of several populations from the numbers of intelligent individuals as a proportion of the population. He concluded that the Greeks of the classical period were the most highly intelligent people that have ever appeared and that the lowland Scots were slightly more intelligent than the English. He considered sub-Saharan Africans to be much less intelligent and the Australian Aborigines the least intelligent race. Galton did not make any estimate of the intelligence of the American Indians or Orientals. However, he considered the Chinese a highly intelligent people. In a letter published in *The Times* in 1873 he wrote that “The Chinaman is endowed with a remarkable aptitude for a high material civilization. He is seen to the least advantage in his own country, where a temporary dark age still prevails, which has not sapped the genius of the race though it has stunted the development of each member of it by a rigid enforcement of an effete system of classical education which treats originality as a crime.” Galton’s estimates are quite close to those obtained in the twentieth and twenty-first centuries from intelligence tests.