Blockchain is a widely discussed topic. It serves important purposes in some industries. But it is also known as being the basis for anonymous payments with bitcoins and other cryptocurrencies, f.e. for unlawful transactions via the internet. What are the data chains good for and which impact do they have now and in future? Let’s crack this tough nut! The lead author writes his draft of the book by using machine learning for his research. 100 curators comment and evaluate the draft. The final book is easy to read for all of us, including those without any IT background.