This book covers the hype, the potential and current tensions in using Second Life for Higher Education. IMO, if you are a research student or educator interested in Second Life then the referencing, modern statistics and discussions regarding Virtual Worlds make this book worth getting your hands on.
Clearly not the cheapest book on Virtual Worlds, however I found it to be satisfactory in covering topics such as entry barriers, communication challenges and opportunities for educators - addressed at the beginning of the book. I particularly found chapter 9 (a context for design learning) interesting in discussion of a collaborative design project carried out by groups of design students. Also, I was glad to see that they didn't cram the book full of pictures from Second Life!
Good Stuff!