"Hudson 3 Essentials" is the second Packt book I've read that I felt was too short. Lesson to myself: check the page count before requesting. (Nothing against short books - I loved "HTML 5 Security" which is a 50 page e-book. But it isn't priced at $30.)
The intro text is short - at 8 pages - which is good. It includes why Hudson is important plus the history of Hudson vs Jenkins. Chapter 2 covers how to install Hudson on four servers in 16 pages. This felt rushed. If you are starting out by explaining that JBoss, Tomcat, etc are servers, a few pages including screenshots isn't enough of an intro to get started. I would have preferred just one in more depth.
If you are keeping track, we are now a quarter through the book.
As for the meat, I liked the coverage of how to configure Hudson. I like the explanation of how to create your own plugin although it felt very rushed and I would have liked a deeper dive. And if I was new to Hudson, I'd have liked to see how to run a job before writing my own plugin.
One good differentiator is that the sample project is a grails one rather than a Java one like most examples.
The last chapter covers how to upgrade to Hudson 3.1.
Overall, there wasn't anything wrong with the book. I'm giving it a neutral rating because I would have liked to see more depth.
Disclosure: I received a copy of this book from the publisher in exchange for writing this review on behalf of CodeRanch.