In late prehistory, the ancestors of the present-day Hopi in Arizona created a unique and spectacular painted pottery tradition referred to as Hopi Yellow Ware. This ceramic tradition, which includes Sikyatki Polychrome pottery, inspired Hopi potter Nampeyo's revival pottery at the turn of the twentieth century. How did such a unique and unprecedented painting style develop? The authors compiled a corpus of almost 2,000 images of Hopi Yellow Ware bowls from the Peabody Museum's collection and other museums. Focusing their work on the exterior, glyphlike painted designs of these bowls, they found that the "glyphs" could be placed into sets and apparently acted as a kind of -signature. The authors argue that part-time specialists were engaged in making this pottery and that relatively few households manufactured Hopi Yellow Ware during the more than 300 years of its production. Extending the Peabody's influential Awatovi project of the 1930s, "Symbols in Clay" calls into question deep-seated assumptions about pottery production and specialization in the precontact American Southwest.