I found this book and Katie's method very helpful in dealing with my long-term anxiety problems.
Her method is similar to CBT, but more straightforward, easy to use and much more effective as a result. What was especially helpful to me is what she says about negative thinking and how it is necessary to find a stressful thought that is causing the way you feel. For years I've been struggling with debilitating physical symptoms of anxiety. I have used CBT with some success, but most of the time I was just feeling unwell, while not really thinking any negative thoughts (or so I thought). It might appear straightforward, but even my therapist of 3 years could not explain this to me in a clear way, when I kept saying that I have no negative thoughts to challenge - 'I do not think anything, I am just feeling ill'.
I have noticed a big improvement in a way I feel and my general attitude to life and stressful situations.
Unlike some other reviewers of her books, I did not find Katie Byron patronising: she communicates in a simple way that some might find simplistic, but, for me, her method really works, and the benefits definitely outweigh the minor annoyances her communication style might cause.