An in-depth exploration of the history, authentication, and modern relevance of Codice Maya de Mexico, the oldest surviving book of the Americas. Ancient Maya scribes recorded prophecies and astronomical observations on the pages of painted books. Although most were lost to decay or destruction, three pre-Hispanic Maya codices were known to have survived, when, in the 1960s, a fourth book that differed from the others appeared in Mexico under mysterious circumstances. After fifty years of debate over its authenticity, recent investigations using cutting-edge scientific and art historical analyses determined that Codice Maya de Mexico (formerly known as Grolier Codex) is in fact the oldest surviving book of the Americas, predating all others by at least two hundred years. This volume provides a multifaceted introduction to the creation, discovery, interpretation, and scientific authentication of Codice Maya de Mexico. In addition, a full-color facsimile and a page-by-page guide to the iconography make the codex accessible to a wide audience. Additional topics include the uses and importance of sacred books in Mesoamerica, the role of astronomy in ancient Maya societies, and the codex's continued relevance to contemporary Maya communities. This volume is published to accompany an exhibition on view at the J. Paul Getty Museum at the Getty Center from October 18, 2022, to January 15, 2023.