This volume deals with legal issues concerning Russias annexation of Crimea and intervention in the Donbas, so-called frozen conflicts and hybrid warfare, the use of courts and tribunals to address armed aggression, and the implications of recent events for the security guarantees connected to nuclear non-proliferation. Continuing from the first volume, which contains Parts One and Two on Chechnya and the Baltic States, this book is comprised of Part Three --Ukraine and other successor States: Territorial Integrity and its Challengers in the Post-Soviet Space; Part Four -- Intervention and International Law; Part Five -- Legal Proceedings and Unlawful Claims; and Part Six -- Non-Proliferation after Budapest.