A natural user interface (NUI) refers to an interface that is effectively invisible or becomes invisible with successive learned interactions. Current and next generation development of computer games, mobile devices, and desktop applications feature 3D interaction. This book deals with NUI design for the input hardware such as multi-touch, kinect, wiimote, and others, with the output as a regular display producing 3D graphics. The key attraction of this book is the hands-on approach and the affordability of the hardware used.