Just finished reading this book from front to back. This book is a great introductory book to Unity3d. It walks you through the process of putting a game together from beginning to end. The book spends a large portion of time on coding in the middle. By the time you finish, you will be comfortable using unity's Javascript, but you will still need to study the language much further using the unity documentation or some other source to learn more about all the unity specific functions and classes. It should be noted that you don't need to be a javascript expert to use unity. Unity's implementation is actually a little different from regular javascript anyways. You only need the knowledge of core javascript, not client side. If you know actionscript 3, you're golden as it's basically the same. Knowledge of any basic programming language like java or c++ is all you really need. The book won't show you much of how to make you're own textures and doesn't talk about modeling characters and animation rigging, but I didn't and don't expect it to. It's about the unity3d engine, not modeling.
There are definitely quite a few errors in this book. However, it does not deserve the low ratings it has. I wouldn't hesitate to recommend this book to anyone. It should be noted that on the very last page, the author explicitly acknowledges that there are "intentional" flaws that the author left in the widget game, but doesn't say what they are... Perhaps the people complaining about the errors didn't even read the whole book? Anyways, the author should have pointed out where the mistakes are in the book as she put them in. At a couple points, complete sections of code were missing... and there were plenty of typos. I wonder if the author just said there were intentional errors at the end to excuse the poor proofreading? Despite all the errors, the book is still great; not excellent, but great. The errors are all minor. If you can't figure them out, you should probably find another career because you are bound to make tons of errors as a programmer/game developer.
My only complaint is that it didn't go in to more detail on certain things, but then again, this is an introductory book. It should be noted that this book is written for unity3d version 2.x, but it will work for 3.x. The only difference is a couple menu options are changed when viewing specific things. I wish there were more books on unity3d that were up to date and went in to more depth on all aspects of the engine. I'm not aware of any "advanced" unity3d books that are out yet, at least at the time I'm writing this. Considering how few books there on unity at the time of this writing, the author should be applauded for her contribution.