A guide to the Mayan Ruins of San Gervasio on the island of Cozumel, Mexico. The guide begins with a description of Cozumel’s early history, starting with the earliest pre-Maya inhabitants, continuing through the Mayan period of occupation and the island’s subsequent discovery and conquest by the Spanish. Other sections include descriptions of Mayan culture, religion, writing system, mathematics, and daily life. The guide also contains a self-guided tour of San Gervasio, which leads the reader building by building through the site and contains floor plans, reconstructed views of the original structures, and descriptions of their use and history. The final section of the book describes the workings and history of the Mayan calendar and the relevance of the date 2012 to the Mayan Long Count.