This textbook provides an overview of the general functioning of international law, rather than presenting an extensive overview of the immense developments of international law in the last few decades. These developments cover a wide range of topics, including the regulation of the subjects, sources, state responsibility, the means of dispute settlement, and the increasingly problematic relation to domestic jurisdictions. In addition, substantive international law has expanded into numerous branches, such as the law of the sea, environmental law, jurisdictional immunities, human rights law, investment and trade law, and international criminal law. Due to its concise nature, this book will be an incentive to students at first degree level to study the subject, while complementing the possible use of a syllabus in the public international law course. The basic character of the narrative is also meant to help attorneys understand how intertwined international law and domestic rules are, which they interpret and apply on a daily basis. And this may result in the use of many more arguments in their pleadings before a national court.