This book is the result of a research project funded by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG), which also supported its publication. We wish to express our gratitude towards the DFG for this assistance. Further, we wish to thank the student assistants subsequently active in the project: Maria Busse, Carolin Damm, Katja Frey, Ulrike Pollin, Luise Sch?ne, Michael Sellner, Eric Urzowski. Special thanks go to Katrin Rentzsch who contributed to Part D. IV. and considerably supported the proofreading and, of course, to Susanne Prater (secretary) who was in charge of the final editorial work.