I would like to thank everybody who made the publication of this book possible. The book is a substantially revised and expanded version of my Ph.D. thesis entitled “Reconciliation of Major Legal Systems Under The Umbrella of International Criminal Law: A Study on the Law on Mens Rea” that was successfully defended in January 2011. My gratitude goes to the host institution—Faculty of Law, University of Copenhagen. It has been a great pleasure to have earned my Ph.D. degree within the walls of the University where at the moment I work as an associate professor. The thesis was written under the thoughtful supervision of Professor J?rn Vestergaard whose comments on the early drafts were invaluable. I am immensely grateful for his continuous support, encouragement and belief in the success of my work. I could not wish for a better supervisor. I would also like to thank Dr Christoffer Wong for his feedback and comments during the seminar on the preliminary evaluation of my thesis in early 2010. I extend my special thanks to the members of my Ph.D. evaluation committee, Professor William Schabas (National University of Ireland/currently Middlesex University), Dr Mohamed Elewa Badar (Brunel University) and Professor Jens Elo Rytter (University of Copenhagen). The written assessment as well as feedback during the public defence of the thesis determined to a great extent the structure and contents of this book. The significant part of this project was carried out during my research stay at the Lauterpacht Centre for International Law in Cambridge from September 2009 until February 2010. My gratitude extends to everybody who made my stay at the Centre most convivial. Some parts of this book were heavily edited and re-written during my stay as a Visiting Professional with the Appeals Division of the Chambers of the International Criminal Court in May-September 2012, which gave me a unique opportunity to get an invaluable insight into the workings of the Court.