This handbook represents an attempt to convey the extraordinarily exciting point that international law (IL) has reached today, both as an academic discipline and as a working system of law. In disciplinary terms, legal theorists have engaged with international relations (IR) and other academic fields to offer new, sophisticated ways of tackling – and going well beyond – old questions about the authentic “legality” or otherwise of international law and its essential nature, effectiveness, content and sources, the community it serves as well as its future potential. In so doing they have reinvestigated the history of international law, questioning, among other things, old certainties about its emergence as a by-product of European modernity, its emphasis on state sovereignty, its embodiment of a “standard of civilization” as determined by its European members, its relation to natural law and other moral, religious and ideological doctrines and the degree to which it helped to legitimate oppression of indigenous peoples and was complicit in other acts of imperial exploitation. As far as the practice of IL is concerned, the twenty-first century has already presented not only extensive and complex challenges that have sometimes seemed to indicate the fragility of IL but also responses to those challenges alongside other
developments that seem to point to its robustness and indeed its growing significance. The seeming powerlessness of the law of force in the face of multifaceted assaults on it from various quarters coexists with far reaching extensions of the law of force since the end of the cold war. The same picture of an underlying vitality apparent in the constant dialectic of challenge and response can be seen in developments in the IL of the environment, trade, criminality, human rights and other areas, while its centrality to some of the key issues of the day is apparent in its role in serious international problems such as terrorism, refugees and the many difficult issues relating to international distributive justice.