In the course of more than half a century, Johann Friedrich Blumenbach put together an "apparatus" in support of his anthropological research of which the main part consisted of some 240 human skulls. This chapter describes the development of the skull collection up to the year of Blumenbach's death, adding an overview of the posthumous history of the collection. It emphases on the first decade of the acquisition of skulls, and explores the question at what times and in which ways the material proved formative of, and significant for, Blumenbach's work. In recent decades, Blumenbach's skull collection has been rediscovered for its value as "biohistorical documents" that can be applied to forensic anthropology and medicine, to the history of medicine, and to paleopathology, archaeology, and ethnology. A growing number of original skulls at his disposal subsequently convinced him of the significance of skull morphology for physical anthropology.