This book covers all the classes of the SpriteKit framework required to develop professional iOS 2D games. All the explanations and code samples have been tested with the latest iOS 7 SDK version. The following subject areas are covered in this book:  Introducing the SpriteKit framework and explanation of the available classes.  Explaining in detail the Node tree.  Animating scenes.  Implementing and understanding the physics subsystem.  Implementing collisions and contacts  Adding sounds, emitters and particles to your game