Preface My first memory of the subject of this thesis is my own ignorance. In Septem-ber 1995, Dorothea Wagner had arranged for the newer members of her working group to attend a symposium held in Passau. The theme of the event was manifested in its title, Graph Drawing, and I wasn't quite expecting to plunge into my new area of interest. After all, mathematicians and computer scientists were going to speak about pictures of binary relations. Things turned out different from what I expected, obviously. And it is my sincere hope that some of the excitement I find in graph visualization has found its way into this thesis. Taking us to this particular conference is only one good Dorothea Wagner did us. It is with great pleasure and deep gratitude that I acknowledge her supervision and support. She would teach me many different things (sometimes without even knowing), give me directions, listen to my outlandish ideas, let me go to conferences, introduce me to amazing people, and do all the other things a student can hope for, but never expect from his supervisor. Hopefully I can return at least some of this someday. Many people have contributed directly or indirectly to this thesis and I apologize for mentioning only a few. Thanks to Michael Kaufmann, who readily agreed to be a thesis reviewer, and Marc H. Scholl and Volker Schnei-der for joining my examination committee. From Graph Drawing '95 I returned to Konstanz with the urge to find graphs that would be interesting to visualize, and I vaguely recalled a friend mentioning " political networks " or such (credit goes to Natascha Füchtner). To make a long story short, by June 1996 an interdisciplinary project group was set up, starting to explore the visualization of social networks. Wagner was an invaluable experience from which I profited both professionally and personally. In similar, and sometimes also completely different, ways I benefited from 1 Financially supported by the Ausschuß für Forschungsfragen der Universität Kon-stanz.