While this book does deliver on it's promises, it is not the most comprehensive resource you can find on the topic. The authors will walk you through some elementary aspects of the Joomla cms, but won't offer you much help if you really want to dig deeper. Joomla! 3 - In 10 Easy Steps will get you started, but doesn't deliver much more than a very basic start.
The book suffers - albeit only slightly - from some grammatical and editorial problems. The occasional missing word and the wrong conjugation of verbs lead me to believe that there are some translation issues. All of this could have been avoided with a little closer editing prior to publication.
All of that said, it wasn't a bad starter resource for the price (I purchased the kindle version).