This book aims to respond precisely to the need of clarifying the functions of school and of proposing a conviction in order to believe in the permanent value of the school institution, which promotes the integral formation of all and of each person. For this purpose the author analyses in a rather documentary and not exhaustive way, some dictionaries and pedagogical encyclopedias, as well as the two international reports regarding education. To think positively and to engage ourselves for school education means to love the future of humanity.