This book fills an important gap in the literature on energy security in the gas sector in the European Union. Whilst the emphasis is often on energy security in the oil sector, the gas sector has grown in importance in recent decades, with increasing liberalization raising critical questions for the security of gas supplies. The share of gas in Europe's energy mix is rising and the differences between the politics and economics of gas and oil supply are becoming more pronounced. The author sheds light on the state of EU energy security in the gas sector, its interdependence with external suppliers and the current gas strategy. He examines the role of energy companies, EU member-states and EU institutions, locates the main developments in the gas sector and focuses on the principal challenges posed by such fundamental changes. The author scrutinizes the EU's relations with its main gas supplier, Russia, as well as with alternative suppliers, elaborates on the key infrastructure projects on the table and their principal ramifications, and discusses the main policies that member-states pursue to achieve energy security as well as the EU's internal contradictions. The book concludes with policy recommendations, particularly in the light of tougher environmental regulation.