Unity offers two main languages to develop games. C# and JavaScript. Most of the tutorials online are using JavaScript but C# is richer and more mature language. This can be both advantage and disadvantage. The book uses C# as the language of choice. But the author made sure to rewrite all examples in JavaScript too!
The book starts from the very beginning and more advanced developers can easily skip first few chapters. It goes through Unity basics and mobile basics - very useful since Unity is a multiplatform engine. Everything is explained on an example and everything explained is used in a game.
I was very surprised that the author included four complete games. Whether you want to build a simple board game, 2D scroller or 3D game, you can find an example in this book. The four games are: Tic Tac Toe, Angry Birds, 3D space shooter game and 3D tank battle. The games could use a lot of polishing, but of course that is not the purpose of the book.
Some parts of the book use Unity Pro, the paid version, but you can use the book with the free edition of Unity as well.
For more information, see Packt website. You can get the book at Amazon in paperback and kindle version.