Cultural diversity, because it is perceived to have significant security, developmental, and social implications, is fast becoming one of the major political issues of the day. At the international level, it overlaps with the now extensive debates on multiculturalism within states. This work shows how cultural diversity challenges the understanding of international relations as relations between states and, by looking at the issue through the magnifying glass of an international organization, offers innovative insights into the interplay between various levels of international society. The book examines in particular the role of UNESCO, the only United Nations agency responsible for culture and the main forum for international diplomacy on the issue of cultural diversity.