This book is a good introduction, but is *very* light in details. Many things are covered very superficially and will be enough to tell you that a topic exists or a few details about it, which you will need to really spend time outside the book (or with other material) to fully understand. The chapter on functions was a good example of this, or channels.. enough to get an idea of the subject, but little detail or concrete examples. If you're an experienced C++/C programmer than you probably fill in a lot of the blanks (but you're probably also not reading this book).
That being said, for the price this "micro book" isn't a bad deal, and I was able to quickly digest it and make concise notes on things to follow-up on.