Huxley was one of the first adherents to Darwin's theory of evolution by natural selection and advanced its acceptance by scientists and the public. Man's Place in Nature was explicitly directed against Richard Owen, who had claimed that there were distinct differences between human brains and those of apes. Huxley demonstrated that ape and human brains were fundamentally similar in every anatomical detail, thus applying evolution to the human race.

Introduction to volume VII, I. On the natural history of the man-like apes., II On the relations of man to the lower animals., III On some fossil remains of man.