No field of legal scholarship or practice operates in the world of private international law as continuously and pervasively as does international arbitration, commercial and investment alike. Arbitration’s dependence on private international law manifests itself throughout the life-cycle of arbitration, from the crafting of an enforceable arbitration agreement, through the entire arbitral process, to the time an award comes before a national court for annulment or for recognition and enforcement. Thus international arbitration provides both arbitral tribunals and courts with constant challenges. Courts may come to the task already equipped with longstanding private international law assumptions, but international arbitrators must largely find their own way through the private international law thicket. Arbitrators and courts take guidance in their private international law inquiries from multiple sources: party agreement, institutional rules, treaties, the national law of competing jurisdictions and an abundance of “soft law”, some of which may even be regarded as expressing an international standard. In a world of this sort, private international law resourcefulness is fundamental.