I have read a lot of software books, and this one I think is one of the best. I'm a professional software developer and I have been tracking the development of react.js for some time. React.js isn't like other frameworks as its comes in lots of little bits, which makes its a bit difficult to understand the whole system. I bought this book to read on holiday, mainly to have a source that went through all the steps.
Yes, the book did cover all the steps but it also has sections on architecture, strategies, best practice, performance tuning and unit testing. The combination of the two means it is a really comprehensive resource. Well done to the Author.
One small down side, which I knew before a bought. The book describes the use of Flux for stores, whereas the go-to library for that is now Redux. However I forgive the authors for that as Flux is the standard approach and Redux is pretty new.
UPDATE: The Author of the book saw my comment and produced a new chapter using Redux instead of Flux (great service!). See his comment below for the link to the new chapter.