Phil gives a very good summary of the book here.
I was very impressed with the book from start to finish and found it hard to put down. It started off fairly light talking about the different types of identifiers that we have but then moved onto some very hot identity topics (especially prevelant in the UK at the moment) such as National ID cards. The book had some very good analogies which helped to explain topics or put them into context.
Jim lays out some very strong arguments for why Identification shouldn’t be the ‘default’ behaviour.
If you are looking for a book to read, I would highly recommend it.