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