The book presents the National Institute of Statistics and Geography, what is and how it has developed over time, since it was founded in 1983. The Institute is today an eminently technical and at the same time autonomous body of the Mexican State.Beyond a chronology of events, this book raises two needs that have marked the Institute's evolution: the first, to properly measure the many components of reality, whether social, economic or natural; and the second, decisive for the public's trust and whose absence would invalidate the purposes of the previous need, to preserve the information from any consideration, other than strictly professional, in all stages of its production and dissemination.This work conveys INEGI's transcendence as an indispensable institution for the country to respond to the fundamental question, common to all human beings: to know and understand the reality of their environment.