Comparing to other books of the Bible family, this book is not satisfactory. It's short of enough figures that can give readers a vivid description of what these codes can make. And the real-world codes are also insufficient. The book is divided into too many chapters, which makes the whole book disordered. The 150-page Appendix is the only highlight of the book. Readers can easily query the usage of keywords. For sure, the book is not suitable to a beginner.