The good stuff starts around chapter 4 and ends before the conclusion, if you're looking for scientific information.
I saw a therapist who recommended it. I've never been a fan of the "Take back your life!" approach to managing mental health issues or otherwise treating them as something that isn't normal. This book does that quite a bit in the introductory chapters and the conclusion is literally called Take Back Your Life. If I could roll my eyes, I would. It felt patronizing.
The actual content from chapter 4 to 13 is pretty good. It clearly lays out where anxiety comes from and what to do about in a straightforward, easy to understand way, without any of the self-help stuff that's always been my least favorite part of talking to therapists.
I got the Kindle book thinking it would be a good pocket reference to carry around on my phone, and I think it would be if you diligently marked the sections that teach you how to calm your anxiety down. I didn't, and if you've been in therapy for a while, you probably don't have to do that. For someone picking this up because it's the most accessible option to them for helping with anxiety, however, I think it would be invaluable.