Since the 1950s, the right to conscientious objection to military service in international human rights law has excited the interest of both non-governmental and inter-governmental organizations in a variety of contexts. This book examines the subject, beginning with an exploration of the concept of conscience and its evolution with a view toward understanding the meaning and potential scope of the right to conscientious objection from a legal perspective. It then investigates the right to conscientious objection as a legitimate exercise of freedom of thought, conscience, and religion. Özgür Heval Çinar analyzes human rights law at both the international and regional level, examining UN, European, and Inter-American mechanisms.