Describes the technical examination and conservation treatment of an important manuscript from post-conquest Mexico that contains eight fold-out Nahuatl pictographs from Huejotzingo on native papers. Examination includes a study of the Native American and Western papers, inks, pigments, sewing structure, collation, and format. Conservation treatment of the text includes disbinding, treatment of the text with nonaqueous deacidification, reversal of silking, mending, and rebinding. Treatment of the drawings includes consolidation, flattening, and mending. An adaptation of the traditional technique of Mexican papermaking is used for mending the drawings. A study of early 16th-century bindings at the Archivo General de la Nación in Mexico City is used to aid in the design of the new binding for the Library of Congress manuscript.