Introduction. A polymorphic issue requiring a global and asymmetric approachChapter I. Beyond the legal discourse: Geopolitics, Private International Law and the admission of foreign law 1. Those early days when PIL did not exist 2. The emergence of the first PIL responses 3. A step further: The development of the principle of comity (and vested rights) 4. The paths diverge: Continental Europe, Anglo-Saxon countries and Ibero-America 5. Diving into the fog: Admitting, as a rule or exception, the possible application of foreign law Chapter II.

The playing field for foreign law: The pier and the quicksand 1. First: The changing terrain for foreign law 2. Second: The end of the State's judge as the sole actor in the process of applying foreign law 3. Third: The evolving and relative meaning of "application" of foreign "law" 4. A slippery issue and the fluctuating reality of PIL: Not such a beautiful friendshipChapter III. The nightmare in practice: How is foreign law applied? 1. The application of foreign law by national authorities 2. The system in practice: The link between the treatment of foreign law before national authorities and its legal, factual or hybrid consideration 3.

Foreign law before State courts 4. The application of foreign law by State non-judicial authorities 5. A fully particular world: The application of the law governing the substance of the dispute by the arbitratorsEpilogue. The never-ending story . until the consolidation of AI? Bibliography.