With the negotiation of a set of parameters for an eventual Joint Comprehensive Plan of Action, the shape of a final deal between Iran and the P5+1 group of countries (the United States, Britain, France, Germany, Russia, and China) has emerged.  However, many important provisions of a final deal remain to be negotiated in the coming months.  A critical set of these provisions involves the adequacy of verification arrangements that would be in place to monitor Iran's compliance with a deal.  Tehran's long history of violations, subterfuge, and non-cooperation require extraordinary arrangements to ensure that Iran's nuclear program is indeed peaceful.  A priority of the on-going negotiations is establishing legally binding measures guaranteeing this adequate verification.