As I was preparing to write an online review I found myself asking why should anyone else read this book instead of, say, start working on a project and search online for whatever they need?
The answer is that books tend to not assume an existing map of conceptual knowledge, but instead provide it. Moreover, good technical books provide a sense of structure and unity that enable the learner to achieve both breadth and depth of knowledge. Just by looking at the contents of a technical book, one can draw conclusions about the nature of the subject.
Spending any significant amount of time studying the subject and especially applying the knowledge through projects results in unparalleled understanding and understanding is, well, everything.