This manual is the result of the joint work of professors who are or have been linked to the main Catalan universities (Universitat de Barcelona, Universitat Autònoma de Barcelona, Universitat Pompeu Fabra, Universitat de Lleida, Universitat de Girona, Universitat Rovira Virgili i Universitat Abat Oliba CEU), it provides the essential foundations of private international law through lessons covering all sectors of the subject -international judicial competence, international cooperation of authorities, recognition and enforcement of foreign resolutions and determination of applicable law- covering both the general and special parts of the discipline. The exhibition unfolds a concise presentation, but at the same time complete, of each of the lessons, also relying on practical cases and the most up-to-date jurisprudence (july 2023). This makes this manual a useful tool for both undergraduate and master's students, and for legal professionals who have to resolve cases of both private international and interregional law.