It took me over five years to write this book. Finishing my research project and thus finishing this book would not have been possible without the help of many friends of mine. Thus, the first thing to do is to say 'Thanks a lot' . This means at first place the Evangelisches Studienwerk Haus Villigst. They gave me a grant for my work, thus laying the important financial grounds of everything I've done. There is such a large number of friends I worked and lived with over the last few years that I cannot possibly mention them all by name, but I'll try, anyway: So, thanks Christiane, Gilbert, Maik, Karl, and everybody else feeling that his or her name should appear in this list. And, of course, thanks Franz Haslinger, for letting me do whatever I wanted to - and for even encouraging me to stick with it. One more thing I'd like to mention: Although this work is based on very heavy use of computer power, it is my special pride to say that not a single penny (i.e. Deutschmark) had to be spent for software in order to do this work. Instead, all that has been done has been done by free software. Thus, I would like to mention some of my most heavily used software tools in order to let you, the reader, know that nowadays you don't depend on big commercial software packages any more.