The Unidroit Principles of International Commercial Contracts provide an excellent and practice proven tool for cross-border contracts: They constitute a neutral and pragmatic business oriented contractual regime for cross-border contracts They contain multiple solutions to typical contractual questions regarding the life of a contract, often by way of a compromise between civil and common law They have been referenced in hundreds of decisions of arbitral tribunals or national state courts They have been endorsed inter alia by the United Nations Commission on International Trade Law (last in 2021) and the Union Internationale des Avocats (2020) bringing together through its bar association and individual members approximately two million lawyers in more than 110 countries. Thirty years after their first publication, it is arguably malpractice to ignore them. In this fully revised and enlarged 2nd edition, the commentary continues to analyse the Unidroit Principles article by article from a practical perspective, while always discussing alternative courses of action, where they apply. The commentary includes proposals for choice of the Unidroit Principles' clauses and practical guidance for their use as template, or to supplement the CISG or national law. In addition to arbitral and state court decisions and recent literature, the 2nd edition includes an in-depth analysis of extensive legislative material. The author is a German practitioner with international training and familiarity with both common and civil law. He has been admitted to the New York Bar and also teaches at the University of Hamburg as a Professor of Law. The author is using the Unidroit Principles for more than 20 years in his commercial and arbitration practice, in recent years on a daily basis in multiple industries. As he shares his experience under the Unidroit Principles, the commentary can also be used as a practical guide and checklist of issues to consider in international contracting. Die Unidroit Principles of International Commercial Contracts sind das ideale Instrument für grenzüberschreitende Verträge: sie bilden ein neutrales, pragmatisches und wirtschaftsorientiertes Regime für grenzüberschreitende Verträge