This book studies Brazilian legislation for children and adolescents, with an emphasis on adolescents who have committed offences. The study begins by investigating violence against children and young people, briefly reviewing the historical evolution of Brazilian legislation. The study then seeks to understand the criteria used to establish the starting point for criminal responsibility, including the use of comparative law. Finally, a debate is held on the proposals to change the age of criminal responsibility in Brazil, in which the arguments against and in favour of changing the paradigm adopted in the Brazilian legal system are debated, as well as the consequences that such changes may have.