Mobile and ubiquitous technologies can potentially change the role of information and communication technology in human lives. Empirical, human-centered approaches are emerging as an alternative to technology-driven approaches in the innovation of these technologies. Three necessary empirical stages, intertwined with analytical ones and with each informing and grounding the succeeding stages, are analyzed. First, needfinding is utilized to discover societal and individual demands for technology. Second, observational and experimental studies examine the social and cognitive preconditions for interaction. From these two steps, a hypothesis is formulated regarding how technology will change existing practices. Finally, this hypothesis, embodied in the design of a prototype, is tested in a field trial. Four design cases illustrate the value of empirical grounding.