International human rights law grants individuals both rights and responsibilities. In this respect international criminal and international humanitarian law are no different. As members of the public international law family they are charged with the regulation, maintenance and protection of human dignity. The right and duty to disobey manifestly illegal orders traverses these three schools of public international law. This book is the first systematic study of the right to conscientious objection under international human rights law. Understanding that rights and duties are not mutually exclusive but complementary, this study analyses the right to conscientious objection and the duties of individuals under international law from various perspectives of public international law.