Out means Out?

What rules of international law apply to the disintegration of a non-state subject of international law? This question arose against the background of Brexit and its practical effects on international agreements of the EU and its member states. The book first shows that the frequently invoked international treaty law does not provide a suitable basis for discussion to answer this question. An alternative explanatory approach is then analysed: Based on an evaluation of the preliminary work on the Vienna Convention on State Succession in Respect of Treaties, the book justifies an analogy between an EU withdrawal and state separations and argues in favour of treating Brexit as a case of treaty succession.