International investment law and arbitration is its own ''galaxy'', made up of thousands of treaties to be read in relation to hundreds of awards. It is also diverse, as treaty and arbitration practices display nuances and differences on a number of issues. While it has been expanding over the past few decades in quantitative terms, this galaxy is now developing new traits as a reaction to the criticisms formulated across civil society in relation to the protection of public interest. This textbook enables readers to master and make sense of this galaxy in motion. It offers an up-to-date, comprehensive and detailed analysis of the rules and practices which form international investment law and arbitration, covering its substantive, institutional and procedural aspects. Using analytical and practice-oriented approaches, it provides analyses accessible to readers discovering this field anew, while it offers a wealth of in-depth studies to those who are already familiar with it.