This book expounds the theory of international arbitration law. It explains in easily accessible terms all the fundamental concepts of arbitration, from separability of the arbitration agreement to competence-competence over procedural autonomy, finality of the award, and many others. It does so with a focus on Swiss international arbitration law and jurisprudence, which are among the leading ones globally. Yet, its reach is broader than a commentary of Chapter 12 of the Swiss Private International Law Act as the foundations of international arbitration are common to most arbitration systems nowadays; the discussion contains numerous references to comparative law and developments. In addition to presenting the law extensively, the book discusses the practice of international tribunals. Written by two well-known specialists – Prof. Kaufmann-Kohler being one of the leading arbitrators worldwide and Prof. Rigozzi one of the foremost experts in sports arbitration – the work reflects many years of experience in managing arbitral proceedings involving commercial, investment and sports disputes. That knowhow is the basis for the solutions proposed to resolve the many practical issues that may arise in the course of an arbitration. It also informs the discussion of the arbitration rules addressed in the book, from the ICC Arbitration Rules to the Swiss Rules of International Arbitration, the CAS Code, and the UNCITRAL Rules. While the book covers commercial and sports arbitrations primarily, it also applies to investment arbitrations conducted under rules other than the ICSID framework.