Scholarship on regional international courts was until recently almost entirely focused on two courts in Europe: the Court of Justice of the European Union and the European Court of Human Rights. With few exceptions, there was little actual knowledge of how international courts in Africa, Latin America, and elsewhere operate in practice. This book, alongside other publications by its authors Karen J. Alter and Laurence R. Helfer, significantly closes that gap. The book pulls together ten years of research to provide the first in-╉depth empirical analysis of the origins, evolution, successes, and failures of the Andean Tribunal of Justice. It shows how the Tribunal has developed from a little-╉known institution established by a small group of developing states in the Andean region to become the world’s third most active international court. Alter and Helfer also explore the connections between the European Court of Justice, set up in the 1950s, and the Andean Tribunal of Justice. The book’s guiding research question is precisely the extent to which the Tribunal can be understood as a transplant—╉or clone—╉of the European Court of Justice. The Andean Tribunal borrows a set of institutional design features from the Court of Justice. Most significantly, it allows for preliminary references from national courts and administrative agencies and also provides other avenues for private litigants and supranational bodies to access the Tribunal to enforce Andean law. Notwithstanding these institutional commonalities, the authors also clearly demonstrate that law and politics operate in a significantly different way in the Andean region than in Europe. A major finding of the book is that the Andean Tribunal has managed to emulate the success of its European counterpart only in a single issue area—╉intellectual property. The Tribunal has become a major institution in the development of intellectual property rules in the Andean region, but in practically all other areas of Andean integration law its activity and influence is limited. This identification of what Alter and Helfer aptly name an “island of effective international adjudication” is helpful for rethinking the differentiated pathways of other regional courts currently evolving in many corners of the world.