This book investigates when and how East Asians became yellow in the Western imagination. It follows a trajectory that emphasizes an important shift in thinking about race during the course of the eighteenth century, when new sorts of human taxonomies began to appear and new claims about the color of all human groups, including East Asians, were put forward. It also examines how the “yellow race” and “Mongolian” bodies became important subjects in nineteenth-century anthropology and medicine, respectively. “Mongolian” bodies, for example, were linked to certain conditions thought to be endemic in—or in some way associated with—the race as a whole, including the “Mongolian eye,” the “Mongolian spot,” and “Mongolism” (now known as Down syndrome). Finally, the book considers how the Far East came to be seen as a “yellow peril,” a term coined in 1895 and often attributed to Kaiser Wilhelm II of Germany.