Ubiquitous computing is one of the best-known myths in computer science and interaction design, dating back to visionary work at Xerox PARC in the early 1990s. What Dourish and Bell do is to look at how ubiquitous computing today is in fact a reality in many ways, albeit very different from the early visions. They draw on a very high level of scholarship in social science, critical theory and computer science to develop a whole range of aspects or perspectives on ubiquitous computing, many of them real eye-openers and going way beyond "implications for design" in suggesting promising new ways for research and development to proceed. In a sense, it is a fine example of book-length scholarly interaction criticism, and I would like to recommend it as required reading for advanced-level interaction designers.