This book is a great reference for large scale organizations that need a handy reference to the various possible processes and artifacts that could comprise an extensive SOA Governance process.
This book will save you a lot of money by reducing (or eliminating) the need to hire expensive SOA consultants to guide you through the mechanics of organizing and structuring a SOA Governance process.
As you read the book, keep in mind that the authors recognize and point out that this isn't a one-size-fits-all. Indeed, they recognize that smaller organizations may need to scale down the processes to suit their environment.
Governance is a complex topic, so I also agree with another reviewer's comment that the reader will benefit greatly by reading other Governance books (such as Todd Biske's) to supplement their views and perspectives on different approaches.
A gentle criticism:
The book seems to focus primarily on manual processes and identifying Governance artifacts to be produced - but gives scant attention to the techniques and mechanics of automating Governance checks that can be performed via Design-Time and Run-Time policy enforcement. This would be an excellent area to expand on in a future revision of the book - and would be an excellent way of supporting the goal of "Agility" referenced in the title.