In the last two decades, Tangible User Interfaces (TUIs) have emerged as a new interface type that interlinks the digital and physical worlds. Drawing upon users' knowledge and skills of interaction with the real non-digital world, TUIs show a potential to enhance the way in which people interact with and leverage digital information. However, TUI research is still in its infancy and extensive research is required in order to fully understand the implications of tangible user interfaces, to develop technologies that further bridge the digital and the physical, and to guide TUI design with empirical knowledge.

This paper examines the existing body of work on Tangible User Interfaces. This book starts by sketching the history of tangible user interfaces, examining the intellectual origins of this field. It then presents TUIs in a broader context, survey application domains, and review frameworks and taxonomies. The authors also discuss conceptual foundations of TUIs including perspectives from cognitive sciences, psychology, and philosophy. Methods and technologies for designing, building, and evaluating TUIs are also addressed. Finally, they discuss the strengths and limitations of TUIs and chart directions for future research.