I have used Typo3 for more then 6 months now and it's a love-hate relationship. True, it is a complex system, and it took me quite a while to get up to speed. But once mastered, the sheer number of extensions provide an enormous resource that saves you a lot of time when you develop web-applications. I don't see Typo3 only as a content management system anymore, it is a web-application development platform. And that is where this book kicks in. I agree with other reviewers that the book is not very easy for people who get started with Typo3, but once you reach the stage of developing your own extensions, the book will guide you on that path. For beginning users, I would just recommend the videos on the typo3 website, but anybody who wants to get beyond the basics, this book is a must.