This volume deals with legal issues concerning Russia’s 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 nonproliferation. 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.