The ultimate question that runs through all of our law of arbitration is the allocation of responsibility between state courts and arbitral tribunals : If private tribunals assume the power to bind others in a definitive fashion, we must ask, where does this authority come from ? Fundamentally different in this respect from a state judge, a private arbitrator may only derive his legitimacy from that exercise of private ordering and self-government which characterizes any voluntary commercial transaction. This work begins then with the dimensions of that “consent” which alone can justify arbitral jurisdiction. The discussion is then carried forward to explore how party autonomy in the contracting process may be expanded, giving rise to the voluntary reallocation of authority between courts and arbitrators. It concludes with the necessary inquiry into the autonomy with respect to the “chosen law” that will govern the agreement to arbitrate itself.