The author discusses the existing theoretical approaches of semiotically informed research in HCI, what is useful and the limitations. He proposes a radical rethink to this approach through a re-evaluation of important semiotic concepts and applied semiotic methods. Using a semiotic model of interaction he explores this concept through several studies that help to develop his argument.
He concludes that this semiotics of interaction is more appropriate than other versions because it focuses on the characteristics of interactive media as they are experienced and the way in which users make sense of them rather than thinking about interface design or usability issues.
Lots of theory about affordances, semiotics, etc. Little of it is new, and parts are tedious (especially 4.1 and 4.2, which describe the many different views of what affordances are and defend the concept against some supposed attacks). As with so many theory books, the connection with real-world examples is rather weak. The examples also seem rather dated for a book published in 2008.