If you are looking for a summary of what interaction design is, then this is not your place. If you are craving for how it could be, for alternative possibilites, than you found an extremely valid text. Moving from theoretical assumption, the reader is logically guided to design conclusions. Which doesn't mean that the book supports analytic thiking as the only one possibile in design. A quite old book (first edition has more than 10 years now) in a such fast field as Interaction Design, but yet a very innovative one.