The interpretation and application of the competence-competence principle are not uniform across jurisdictions. Conflicting approaches - to the extent, effects, and consequences of permitting an arbitral tribunal to decide on its own jurisdiction and the proper timing for judicial involvement - rest upon significant theoretical and policy concerns that have practical implications. Focusing on Article 8(1) of the UNCITRAL model law on international commercial arbitration, this book thoroughly examines a question of timing: whether national courts should (or could) conclusively settle jurisdictional disputes before or after the arbitrators have determined jurisdiction.