He describes Europeans as "Caucasians," Africans as "Aethiopians," Asians as "Mongolians," Polynesians and other South Pacific peoples as "Malays," and Native people of Turtle Island as "Americans." He also identifies North Africans and Middle Eastern people as "Caucasian."

During this period of great "scholarly" debate over racial anatomy and categorization, Blumenbach is unusual in that he argues that environment is the primary factor in racial diversity and that all humans descend from the same linked family. His book, On the Unity of Mankind, will bring his theories more fully into the public realm when it is published in 1795. People in the U.S. who are invested in the idea of pure Saxon ancestry will resist his category of "Caucasian" because it lumps Celts and Saxons together.