This chapter examines the main features of the centralised approach in general terms before turning to its clearest illustration, the international law of nuclear energy. The examination of the latter follows two main steps. Firstly, the chapter discusses the ‘dual use’ of nuclear technology, for civil and military purposes, as main historical driver for centralisation. Secondly, it analyses the structure and content of the centralised governance of nuclear energy, paying particular attention to the role of the IAEA. The international law of nuclear energy is presented by reference to the legal balance between nuclear cooperation and safeguards, safety standards (prevention, response and reparation) and environmental protection.