A friend of mine (who also stutters) recommended it, so I ordered the book. I still stutter quite a lot and have my ups and downs but now I'm able to successfully control a block during speech much better. I'm not a native English speaker so I translated some of the exercises to my language. It requires a lot of practice and I have to admit I'm a bit lazy. :) But when I do the exercises written in the book, I speak much better (not perfectly but in an easier and more enjoyable way). I like the way that Parry explains stuttering in his book. Maybe it's not the ultimate answer to this problem (I've also read some sceptical comments about the book in this subreddit), but it can help, nonetheless.