The 4th edition of the work "Public International Law" is an enriched and revised record of the regulatory framework of modern international relations. It deals with issues that constitute the core of international law, such as: the basic elements of the system (subjects and sources of international law, international treaties, etc.), its areas of application (territorial issues, law of the sea, new institutions), the international activities of states (diplomatic relations, succession, secession, international responsibility, environmental protection and cultural heritage, etc.), the organization of the international community (United Nations, International Labour Organization), the handling of international crises (peaceful settlement of disputes, contribution of the International Court of Justice in The Hague). The book contains numerous examples of cases from modern history, explanatory maps for the law of the sea, and is accompanied by a rich bibliography and detailed alphabetical index. It is addressed to every scholar, researcher, or practitioner of international law and to every active citizen who wishes to explore the current state of affairs in modern international relations.