I read books about software products when I need to get introduced to the whole picture: architecture, underlying technologies..... In this way I also understand what to search for when I need detailed information or tip and tricks.
Well that's the problem in this case. The book isn't a high-level introduction, it's the official documentation in print. It's the same as the online documentation verbatim. As far as I can see, the differences between the electronic copy that Lulu sells and the PDF provided on the official site are that Lulu's one costs money, has restrictive DRM protections and is presented in a slightly different layout. Furthermore, when the next major release comes out, you can just download another copy from the official site for free, but not so with Lulu.
