The first part compare different style-guides and does some cherry-picking here and there. The result is very informative and luckily comes pretty close to the style I personally prefer. Also, the author does mention JSHint and JSLint right from the get-go. This first part might perhaps seem a bit basic for most readers but the comparison between the JQuery coding guidelines and those of other projects make it quite an informative read.
The second part describes common coding practices like avoiding global variables, loose coupling, exception handling and so on. Personally, this was basically the part of the book I was expecting when reading the title and I was not disappointed. There was some very good stuff in there like how to do exception throwing and handling in a cross-browser compatible manner. Also the drawbacks and advantages of browser-detection vs. feature-detection where described very clearly.
For some of the topics discussed in this part there are already tons of solutions in the popular JS frameworks like JQuery, Dojo and YUI available. Where appropriate the author includes examples from those libraries.
Perhaps the third part could have lost some pages to put those into part two ;-) This third and last part of the book deals with automating what was taught before and making it ready for prime-time via deployment. The tool of choice here is Ant, which receives IMO a bit too much focus here, but given that quite a lot of tools around the JS ecosystem are Java-based this makes sense. That said, it kind of made me skip most of this part since I have already worked with most of the tools mentioned in this chapter before.