This is my second book in the series dealing with the subject-matters of Public International Law. It deals with international (inter-governmental) organizations. It comes to complement my first book on Public International Law, since no book on Public International Law is complete without including chapters on international organizations. International organizations, next to states, are predominant subjects (persons) of contemporary Public International Law, and they play a dominate role on the international stage. This book gives a general overview about the theory of "international organization" and about the most important international organizations: universal, regional and specialized. It mainly discusses their establishment, aims, purposes, activities and organizational structure. The materials provided in this book are, in my opinion, sufficient for the students of the course on international organizations, especially those in the Arab and Third World countries. If more materials are needed, I refer students to the references mentioned in this book.