This book is a translation of an original German 1st edition by Christiane König, published by J.B.Metzler, imprint of Springer-Verlag GmbH Germany, part of Springer Nature in 2020. The translation was done with the help of artificial intelligence (machine translation by the service DeepL.com). The author (with the friendly support of Megan Hanson) has subsequently revised the text further in an endeavour to refine the work stylistically. Springer Nature works continuously to further the development of tools for the production of books and on the related technologies to support authors.