I would think if his only aim is to crush microstakes, then he has to be a pretty knowledgeable source for that level. Even if his book does nothing for you up on higher levels, it would at least help you to get to them. It seems to me (and this is only the opinion of a noob) that playing games at any stakes will require the exact same set of skills, just applied in different fashions. *if anybody disagrees, please speak up so I can squash this line of thinking if it's proven to be stupid.* So if you have a pretty solid control of the basics, I can't see anything wrong with picking up a book that's so narrowly focused. I feel like I have seen some of his content on youtube not long ago, so you can probably get a sample of what he has to offer, see if it's a good fit for you.