This work would not have been realized without the help of many people along the way in terms of writing and rewriting it, and in the publishing process. Therefore, I would like to dedicate the book to all those people who contributed in some way to the book.

Specifically, I would like to mention Tom Brijs, Katheleyn Van den Driessche, Jeremie Achille and Karolien Van Nunen, four excellent and very hard-working students whom I was privileged to guide.

A word of sincere thanks also goes to my colleagues Dr. Nima Khakzad, Dr. Luca Talarico, and Dr. Koen Ponnet, all of whom I am very happy and proud to also call my friends.

Furthermore, I cannot thank enough my colleague An Kempeneers for her very efficient and excellent help with the figures, the index and the list of acronyms of the book. Thank you, An!

I must also acknowledge my parents, Eddy and Iona, who are always helping when and where they can during the most hectic period of my life.

There are many other people who have contributed in some way to the realization of this work, for instance the Wiley production team who I have not explicitly mentioned, but I would also like to thank them.

Finally, I would like to dedicate the book to my wonderful wife Carmen who remained patient and helpful during the – sometimes difficult and demanding – writing process, and also to my ever enthusiastic, happy and very vivid daughter Kari. Thank you both for making me happy!

Once again, thank you all so very much!

Genserik L.L. Reniers