One of the earliest texts written in a Native American language, the Codex Sierra is a sixteenth-century book of accounts from Santa Catalina Texupan, a community in the Mixteca region of the modern state of Oaxaca. Kevin Terraciano’s transcription and translation, the first in more than a half century, combine with his deeply informed analysis to make this the most accurate, complete, and comprehensive English-language edition of this rare manuscript. The sixty-two-page manuscript, organized in parallel columns of Nahuatl alphabetic writing and hand-painted images, documents the expenditures and income of Texupan from 1550 to 1564. With the alphabetic column as a Rosetta stone for deciphering the phonetic glyphs, a picture emerges of indigenous pueblos taking part in the burgeoning Mexican silk industry—only to be buffeted by the opening of trade with China and the devastations of the great epidemics of the late 1500s. Terraciano uses a wide range of archival sources from the period to demonstrate how the community innovated and adapted to the challenges of the time, and how they were ultimately undermined by the actions and policies of colonial officials. The first known record of an indigenous population’s integration into the transatlantic economy, and of the impact of the transpacific trade on a lucrative industry in the region, the Codex Sierra provides a unique window on the world of the Mixteca less than a generation after the conquest—a view rendered all the more precise, clear, and coherent by this new translation and commentary.