What you need for this book
This book is a Unity-focused title, which means you only need a copy of Unity. Unity comes with everything you need to follow along with the book, including a code editor. Unity can be downloaded from http://unity3d.com/. Unity is a single application that supports two main licenses, free and pro. The free license restricts access to certain features, but nonetheless still gives you access to a powerful feature set. In general, most chapters and examples in this book are compliant with the free version, meaning that you can usually follow along with the free version. Some chapters and examples will, however, require the professional version.