This is by far the best unity book I've had the opportunity to read. It's well written, easy to follow, and covers a lot of ground. Unlike other books, throughout the book only one example game is made, but the game is far more advanced than if the author would jump from one game to another.
The book goes through all sorts of unity features, including the landscape engine, particle systems, animation, ui, HUD, physics, scripting (in both c# and javascript) - actually, plenty of space is dedicated to scripting, including a chapter that goes through basic concepts like variables, functions and logic structures, but this is all done in a way that's not dumbed down by any means.
Towards the end of the book you can find descriptions of things often forgotten, including doing finishing touches, optimization, steps to publish on the web or standalone, and so on.
If you want to buy one book on unity, this, in my opinion, would be it.