ABSTRACT
The international relations’ (IR) subfi eld of ‘international organization’ (IO) is quite old and still widening. Although ‘international regime’ and ‘international institution’ became broader terms, no one has suggested using these to indicate the subfi eld. International organization is a set term used by political scientists, as well as scholars from other disciplines such as international law, economics and anthropology. When political scientist Paul Reinsch published his Public International Unions: Their Work and Organization in 1911, he argued that traditional ideas of international law were in need of revision: ‘the realm of international organization is an accomplished fact’ (Reinsch 1911: 4).
