Written by a team of international lawyers from Europe, Asia, Africa, and the Caribbean,this book analyses some of the most significant aspects of the ongoing armed conflictbetween the Russian Federation and Ukraine. As challenging as this conflict is for the international legal order, it also offers lessonsto be learned by the States concerned, and by other States alike. The book analysesthe application of international law in this conflict, and suggests ways for this law'sprogressive development. It will be useful to practitioners of international law working at national Ministriesof Defence, Justice, and Foreign Affairs, as well as in Parliaments, to lawyers ofinternational organizations, and to national and international judges dealing withmatters of public international law, international humanitarian law and criminal law.It will also be of interest to scholars and students of international law, and to historiansof international relations. Sergey Sayapin is Assistant Professor in International and Criminal Law at the Schoolof Law of the KIMEP University in Almaty, Kazakhstan. Evhen Tsybulenko is Professor of Law at the Department of Law of the Tallinn Universityof Technology in Tallinn, Estonia.

Since after the Second World War, the crime of aggression is - along with genocide, crimes against humanity and war crimes - a "core crime" under international law. However, despite a formal recognition of aggression as a matter of international criminal law and the reinforcement of the international legal regulation of the use of force by States, numerous international armed conflicts occurred but no one was ever prosecuted for aggression since 1949. This book comprehensively analyses the historical development of the criminalisation of aggression, scrutinises in a detailed manner the relevant jurisprudence of the Nuremberg and Tokyo Tribunals as well as of the Nuremberg follow-up trials, and makes proposals for a more successful prosecution for aggression in the future. In identifying customary international law on the subject, the volume draws upon a wealth of applicable sources of national criminal law and puts forward a useful classification of States legislative approaches towards the criminalisation of aggression at the national level. It also offers a detailed analysis of the current international legal regulation of the use of force and of the Rome Statutes substantive and procedural provisions pertaining to the exercise of the International Criminal Courts jurisdiction with respect to the crime of aggression, after 1 January 2017."