In this new era of computing, where the iPhone, iPad, Xbox Kinect, and similar devices have changed the way to interact with computers, many questions arised of how modern input devices can be used for a more intuitive user interaction. This book, Interaction Design for 3D User Interfaces, addressed this paradigm shift. The book looks at user interfaces with an input perspective. This book is divided in four parts (I) Theory of input devices and user interfaces with an emphasis on multi-touch interaction; (II) Advanced topics that helps reduced noise on input devices; (III) Hands-on approach to allow the reader gain experience with some of the new devices mention on this book. (IV) A case study that shows how a complete solution, using speech as input. This book provides current state-of-the-art, which allows researchers, developers, and students to understand the direction on the field of input devices and user interaction.