My Background: I'm a QA Director for a video game company that has been working on agile based teams for about 6 years.
I'm about half way through the book so far, but it really wasn't what I was expecting. I was looking for reading material to help new testers understand agile testing and good practices. Instead, so far this book seems to be more about convincing the reader to use agile instead of waterfall, so I can't relate to the intended audience.
There are some good sections in the book that I've highlighted to bring back to my team, but also some things that seemed based on opinion based and that I disagreed with.
If you are working in a badly managed waterfall environment, I'd recommend this book to arm you with reasons to switch to an agile methodology like scrum or kanban.