Salta Province, which lies astride the Tropic of Capricorn in extreme northwest Argentina, encompasses many of South America's major habitats: montane moist forest, thorn forest, lowland desert, highland desert, and deciduous forests. As a result, the area supports a wealth of mammal species and is of great biogeographic interest. This bilingual guide is the first to survey the mammal fauna of a major region of South America, the continent that has the richest array of plant and animal life on earth. The Guide includes information on the natural history, taxonomy, and behavior of all 114 species known to occur in the province, of which many species have been very poorly studied. A key to the families of mammals, depictions of the species, distribution maps, and cranial drawings assist in identification. General information on Salta and its habitats also is provided, as is a discussion of the methods of mammal research.