We want to acknowledge the competent and helpful comments and suggestions by Helmut Podhaisky, Halle University, Germany. To have such a partner in the process of writing a book is a big luck and chance for the authors.

We would also like to express our gratitude towards the reviewers of the first edition of this book, [7], Linda Kann, KTH Stockholm, Hans Petter Langtangen, Simula Research Laboratory, and Alf Inge Wang, NTNU Trondheim.

A book has to be tested in teaching. And here we had fantastic partners: the teaching assistants from the course "Beräkningsprogramering med Python" during the years and the colleagues involved in teaching: Najmeh Abiri, Christian Andersson, Dara Maghdid, Peter Meisrimel, Fatemeh Mohammadi, Azahar Monge, Anna-Maria Persson, Alexandros Sopasakis, Tony Stillfjord, Lund University. Najmeh Abiri also tested most of the Jupyter notebook material which you find on the book's webpage.

A book has not only to be written, it has to be published, and in this process Aishwarya Pandere and Karan Thakkar, PACKT Publishing, were always constructive, friendly and helpful partners bridging different time zones and different text processing tools. Thanks.

Claus Führer, Jan-Erik Solem, Olivier Verdier  Lund, Bergen 2016