Though Immanuel Kant had a large, powerful skull, Carl Gustav Carus did not think it beautiful. He regarded the beauty of Friedrich Schiller's skull, the famous German poet, as an index of harmonious intellectual and artistic accomplishment. Those researchers who studied skulls formed two distinct groups at the turn of the eighteenth century. One group argued that the physical features of skulls – including their aesthetic qualities – represented different human types and were permanent, revealing the mental characteristics of the several races; such physical distinctions permitted the scaling of the races into higher and lower in regard to intelligence, talent, and moral disposition. The other group also made careful measurements of the physical features of skulls but the members of this group contended that such features were impermanent and variable. After some preliminary considerations of the social context and racial classifications, this chapter attends four representative craniologists: Friedrich Tiedemann, Samuel George Morton, Johann Friedrich Blumenbach, and Carl Gustav Carus.