This monograph is a revised version of the results of my Ph.D. research as a graduate teaching assistant at Queen Mary University of London (qmul) from 2015 and 2019. Many people have helped me during this journey. First and foremost, I would like to express my deepest appreciation to my Ph.D. supervisors Prof. Elspeth Guild and Prof. Julia Hörnle. Thanks to Prof. Guild’s guidance for my master’s thesis at qmul, I had the chance to explore the ideas that would soon direct me towards the research subject of my Ph.D. Since then, her invaluable support for my Ph.D. and related research have made it possible for me to finish my thesis and embark upon other journeys. I would also profoundly thank Prof. Hörnle for her continual academic support without which this work would be incomplete. Besides my Ph.D. supervisors, I would like to thank the jury of my doctoral thesis defence, Dr. Orla Lynskey and Prof. Mark D. Cole for their insightful comments. I also had the opportunity to present part of this book at conferences and an earlier version of sections of Chapters 3 and 5 was published as ‘Following the digital footprints of airline passengers: An assessment of the eu-us pnr Agreement with respect to the EU right to privacy and data protection’ in Gert Vermeulen and Eva Lievens (eds), Data Protection and Privacy under Pressure (Maklu 2017). Lastly, I wish to thank my family and everyone whom I have crossed paths with throughout this journey.