This book describes the biodiversity and biogeography of nothern Mexico, documents the biological importance of regional ecosystems and the impacts of human land use on the conservation status of plants and wildlife. It should become the standard source document for the conservation status of species and ecosystems in this region, which is of unusual biological interest because of its high biodiversity and highly varied landscape and biological zonation. Jean-Luc E. Cartron is at University of Mexico. Gerardo Ceballos is at National Autonomous University of New Mexico.