"An Annotated Check List of the Mammals of Michoacán, México" by E. Raymond Hall and Bernardo Villa R. is a scientific publication written in the mid-20th century. The work aims to document the various species of mammals found in Michoacán, detailing their descriptions, ranges, and relevant observations. Through meticulous fieldwork, the authors seek to enhance the understanding of the region's biodiversity. The opening portion of this publication introduces the context of a research initiative facilitated by the administration of President Lázaro Cardenas, aimed at documenting cultural and natural resources in Mexico. Following an invitation to investigate the mammals of Michoacán, Hall, along with Villa and others, conducted extensive fieldwork in 1943 across multiple locations, such as Pátzcuaro and Tacámbaro. The authors outline their goals—recording mammal species' scientific and vernacular names, geographic ranges, and circumstantial information useful for future studies, while also citing previous collections and collaborations that enrich their findings. The initial chapters set the stage for a detailed examination of the region's mammalian fauna, with references to specific specimens and observations that indicate an ongoing commitment to further investigation and documentation. (This is an automatically generated summary.)