Ethnicity and International Law presents an historical account of the impact of ethnicity on the making of international law. The development of international law since the nineteenth century is characterised by the inherent tension between the liberal and conservative traditions of dealing with what might be termed the 'problem' of ethnicity. The present-day hesitancy of liberal international law to engage with ethnicity in ethnic conflicts and ethnic minorities has its roots in these conflicting philosophical traditions. In international legal studies, both the relevance of ethnicity, and the traditions of understanding it, lie in this fact.