From what I see many of the functional solutions described in the book are also available in some form in the Scalaz open-source library, which you both maintain along with many contributors.
Also it seems to me that while the book was being written, there's been an ongoing evolution of the library (e.g. scalaz streams, lenses, actors, scala machines ...) as more elegant or plain alternative solutions appeared.
Now the question is: has the book followed this ongoing evolution? Or did I make a wrong assumption?
The book doesn't explicitly mention or follow Scalaz in any way. This is because we want you to be able to pick up this book 20 years from now, possibly with an old (by that time) version of Scala, and still get the benefits of it. That said, since we are both contributors to the library, Scalaz and the book naturally inform each other. For example, scalaz-stream is heavily influenced by the ideas in chapter 15, and in turn a lot of edits to that chapter came out of practical experience with the scalaz-stream library.