The book is easy to read and understand, and very useful to a LinkedIn novice. Even for the more experienced user there are still a few gems to be discovered. After all, there is a difference between knowing a programme or social medium and getting the most out of it. The book is also a useful reference to check now and then to make sure you have not forgotten a 'trick'.
Reading this book I was kind of pleased to see that I already knew most of it. However, the book did bring some useful tips and 'tools' to my attention that came in useful during my jobhunt - to get the most out of my network (1st and 2nd degree connections) and the companies I was interested in.
Being the medium that it is, LinkedIn is likely to change and modify itself over time, and therefore the book will need an updated edition or addendum. But then, this is valid for any book regarding a fast changing medium or tool (e.g. internet or computer software). Most of the principles and functions are likely still to be found in newer (layout) versions of LinkedIn.