This third edition examines the EU's Third Internal Market package, which marks a watershed in the EU's efforts to introduce effective liberalization of its electricity and gas markets. It comprises five separate legal acts that introduce new rules on: more effective unbundling, requiring real and effective separation of the transmission company from generation/supply and the introduction of the choice between ownership unbundling, ITS, ISO, and ISO+ ** new additional powers for national energy regulators ** a new European Agency, ACER, that brings together national energy regulators ** new transmission bodies, ENTSOE, and ENTSOG, that will be able to take more concentrated and effective action to develop common rules that will result in better market integration ** a new streamlined decision-making process, in which the new Agency and TSO bodies play a leading role, in developing common codes and rules ** new rules on network planning and on customer protection