The theme of this book, 'Historical formulation of the concept of paedophilia and the impact of laws', is to study the changes that have taken place in the concept of paedophilia over the years, as well as the changes in the legal rules that govern the protection of children and adolescents in our legal system. To this end, the term paedophilia is first studied, showing introductory notions of its meaning, origin, forms and the psychological consequences suffered by victims. The aim is then to demonstrate the legal rules protecting minors, from the Letters of Commitment signed by Brazil, the Federal Constitution, the Statute of the Child and Adolescent and the Penal Code, followed by a comparative study of Brazil's protective rules with those of other countries, such as Italy, Spain, Costa Rica and Africa. At the end, all the changes made to the rules protecting children and adolescents are discussed, showing how our legal system has adapted to keep up with changes in society and fill in existing gaps.