My guess is that Trimpey didn't write his own book cover for the purposes of marketing.
A book without any kind of inviting information on the outside isn't going to get anyone to read it.
The first sentence seems benign enough with a disclaimer of "may be enough." The back cover verbiage sounds like a publishing company trying to promote a book. Having said that, I don't hear any "you will" or "you shall" promises. You "can" doesn't' sound particularly like a promise, especially since it doesn't indicate that "anyone can", etc.
I'm not sure what else a book promoter can do to make a topic noticeable among the fray. I hate to admit it, but I am taken in by attractive book covers and phraseology that catches my eye when I am browsing a book store, and I don't pay much attention to the plain brown paper wrappers, also those also have their allure.
Personally, I become more irritated by false claims. I don't think any false claims are being made on behalf of AVRT. If you see one, I'd be interested to know about it since I really think this is a method that works for people who want their own plan unfettered by others' ideas of how they should attain sobriety.
FT