This book presents a contextual approach to designing contemporary interactive mobile computer systems as integral parts of ubiquitous computing environments. Interactive mobile systems, services, and devices have become functional design objects that we care deeply about. Although their look, feel, and features impact our everyday lives as we orchestrate them in concert with a plethora of other computing technologies, these artifacts are not well understood or created through traditional methods of user-centered design and usability engineering. Contrary to more traditional IT artifacts, they constitute holistic user experiences of value and pleasure that require careful attention to the variety, complexity, and dynamics of their usage. Hence, the design of mobile interactions proposed in this book transcends existing approaches by using the ensemble of form and context as its central unit of analysis. As such, it promotes a designerly way of achieving convergence between form and context through a contextually grounded, wholeness sensitive, and continually unfolding process of design.