During the formative period of international organizations, attention was largely1 focused on their “internal” law, i.e. on their functions, powers and procedures under their constitutions and other rules. The assumption that international organizations do not have a common denominator encouraged such introspection. However — to misapply a famous quotation — no organization is an island, entire of itself. For their dealings with the outside world, whether in the sphere of public international law or in that of private law, the internal rules of organizations are relevant but not sufficient.2