Good introduction. The joomla process is well-explained, with good examples. The edition is good. The component analysis is on the weblinks component, but I guess it would be better to explain a more complex component. The same for the subscriptions-component that is built from scratch. The crash-courses (introductory to PHP, OOP, etc) are also good. I guess it worths the price.
This book was way to introductory. It kept wandering into basic PHP, programming and web development topics that already have a very firm grasp on. Worse, the kindle formatting made much of the text unreadable. Quite disappointing.