The second edition of "Thinking in Complexity", like the first edition, was also sold out in less than one year. Meanwhile, Japanese and Chinese translations of the sec- ond editon have been published. Once more I have taken the opportunity provided by a new edition to revise and extend the text. A new Sect. 2. 5 "Complex Systems and the Self- Construction of Materials" is included, in order to ana- lyze the role of complex systems in the dramatic success of supramolecular chemistry, nanotechnology, and the technology of smart ("intelligent") materials. These top- ics lie at the boundary between materials science and life science. In recent years, life science and computer science have been growing together in a common field of research called "artificial life". A further new Sect. 5. 5 "From Artificial Intelligence to Artificial Life" has been added, in which the role of complex systems in the field of arti- ficiallife is discussed. I also use the opportunity of the new edition to make some remarks about the relationship between the Santa Fe approach to complex systems and the methods of synergetics and order parameters which are key concepts in this book. Research into complex systems continues world- wide. I have to thank the readers who have written friendly and inspiring letters from all over the world. Some months ago, a German Society of Complex Sys- tems and Nonlinear Dynamics was founded.