Book excerpt: This book is dedicated to the study of the Mexican nation, providing an overview of its two-hundred-year evolution, and particularly analyzing its contemporary profile, which is characterized by unprecedented social reconfiguration sustained by Mexicans residing abroad. As we will show throughout this book ́s chapters, the Mexican nation has over the past two centuries followed a complex, sinuous trajectory, conflictive at many points, which step by step built the nation as we know it today, a nation that has not by any means exhausted its vitality or its impetus for continuing to evolve.From now on, the Mexican nation cannot be understood solely on the basis of the population residing within its borders. It must be recognized comprehensively, considering, simultaneously and in equal conditions, people living abroad who hold Mexican nationality. The path ahead is extraordinarily complex, without a doubt. Taking into account its social composition, the 21st century Mexican nation is based and reproduces itself simultaneously within and outside of the territory; therein lies its transterritorial nature.The author is a professor in the UNAM University Program in Development Studies. He has been president of the El Colegio de la Frontera Norte and Commissioner for the National Migration Institute. He is a member of the National System of Researchers and has published widely on topics of migration, northern and southern border studies, regional political issues and modernization of local governments.