This is a book about design and philosophical issues in the field of Human Computer Interaction (HCI). The author examines how computer systems, when thought of as technical entities, are essentially "underdefined", since in the end they are always designed for people. He also looks at how modern phenomenology (a strand of modern philosophy) and social anthropology offer us methods to move towards an embodied, encultured approach to HCI design.
Particularly interesting is the informed discussion of various computer development models in which human users can use real objects to stand for themselves. For example, the "Illuminating Light" application for testing hologram-making scenarios uses "phicons": physical icons such as mock beam-splitters, laser sources and mirrors which also represent their "computer" meaning in the system. These phicons "stand for themselves" - as the user moves them around a table, the software calculates beam angles and displays those via a projector onto the same table, thus making the user experience of testing holography set ups more tangible and intuitive. (Side note - holography set-up is a tricky old business, at least for this reviewer, so this application would also be useful outside of mere "prototype" contexts).
The book contains lots of example scenarios, the author draws particularly on experiences from his career in "innovative software" development with Xerox plc. In this way, the book manages to stay relevant from an engineering design perspective.
Dourish also introduces - in an easy-paced "philosophy for the mildly interested" style - various philosophers from the 20th Century whose contributions to the ideas of our existence as "embodied" and "interactive" selves have both reoriented modern philosophy and enabled philosophy to contribute theoretical ideas to other fields. He mentions Merleau-Ponty, Heidegger, Andy Clark, and so on - references are provided for further reading, though I reckon the basic treatment in the book - brief explication with concrete examples in HCI practice - is pitched just right for it's target audience, the HCI community.