Interactive systems in the mobile, ubiquitous, and virtual environments are at a stage of development where designers and developers are keen to find out more about design, use and usability of these systems. Ubiquitous Computing: Design, Implementation and Usability highlights the emergent usability theories, techniques, tools and best practices in these environments. This book shows that usable and useful systems are able to be achieved in ways that will improve usability to enhance user experiences. Research on the usability issues for young children, teenagers, adults, and the elderly is presented, with different techniques for the mobile, ubiquitous, and virtual environments.