Keane's racial theories were published first in Nature in 1879–81. He affirmed the specific unity of human beings in his 1896 text Ethnology, even if his views had some other implications. He produced racial typologies, in his expository writings; they were more systematic than those of John George Wood and Robert Brown, and were intended for rote learning.
Evolutionary tree from Keane's Ethnology (1909).
Keane was out of step with the anthropology of the time, preferring linguistic data to that of physical anthropology and came to occupy a marginal position in the emerging scientific discipline.