An odd book. Interesting as a survey of a field of related and interlocking ideas, but confusing insofar as these ideas are not really embedded in any overarching narrative. Overall, the impression is one of confusion, as the concepts in question seem to bend and shift depending on the context in which they are used; nothing is certain and everything is to a degree both assumed and contested. Indeed, demonstrating this seems to be the point of the book, but the point is exhibited rather than argued for, which after a while becomes disorientating as one loses and sense of having a solid grip on the concepts in question. One also worries that the conceptual confusion evidenced is a product not of their aboriginal inconsistency but of confusion on behalf of the author - it would be interesting to see the claims made in the book addressed by experts in the relevant fields.