I would like to thank my family for their invaluable support during the process of writing the book. In particular, I wish to thank Dorina Bobeva, Nadelia Bobeva, Ann Dyson, Charles Dyson, Kenneth Dyson and Denitza Kostadinova. I would also like to express my gratitude to Daniel Brinkwerth, James Cook, Professor Chris Flood, Professor Klaus Goetz, Kirsten Heuschen, Dr Lars Houpt, Professor Adrian Hyde-Price, Dr Alex Jaeckel, Eliza Karamasalo, Dr Natasha Gouseti, Dr Harshan Kumarasingham, Sebastian Lampe, Dr Thomas Mueller-Farber, Professor Mark Olssen, Ralf Schwarz and Christopher Wollin for their intellectual and emotional support during the writing of the book. I also wish to thank the Alexander von Humboldt Stiftung for funding my research fellowship between 2009 and 2011, during which a significant proportion of this book was written. In addition, I would like to express my gratitude to staff at the Chair of German and European Politics and Governance at the University of Potsdam and the Working Group on International Security at the Stiftung Wissenschaft und Politik, Berlin, where the fellowship was based. I also wish to thank my interview partners for their openness and generosity with their time. Finally, I would like to thank my co-author for his patience, intellectual curiosity, wit and friendship which made writing this book a very enjoyable process.