This book has as aim analyzing the concept of control of conventionality as a tool to protect human rights in the Inter American System on Human Rights. In this book it is argued that the application of the control of conventionality is defined by the principle of subsidiarity. In that vein, the protection of human rights through the control of conventionality is a competence that national authorities and, more specifically, the local judges exert primarily. Likewise, this book lies on the idea that the doctrine of control of conventionality is tied to the idea of constitutionalization of the national legal orders and the constitutionalization of the international law through the protection of the individuals as the final end of the transnational principle of rule of law.