Energy, as a matter of security, is the major challenge during the 21st century. The energy mix will change, predominantly to renewable energy sources, followed by natural gas. The EU will be the foremost gas importer by 2030 and the rate of its LNG imports will double by 2020. The UK, France, Spain and Italy import 87% of the EU’s LNG needs. So, diversification of routes and suppliers is an objective of the EU Energy Policy and considered essential to the Union's future energy security . This book, centres on a comparison of different suppliers towards the EU, on the basis of the four indicators of the energy security. Therefore, the role of the Persian Gulf, as the leading gas holder worldwide, in general, as well as Iran and Qatar, as the potential and actual LNG exporters, in particular, for the energy security of the EU will be examined. This book should be especially useful for professionals in Politics, International Relations, Regional Studies, as well as Energy Diplomacy and Security fields.