I'd recommend this book to wiccans and non-wiccans alike. The structure of the book is designed to be read, considered and used as a guide over a 13 month period, though you could easily read the whole thing through and do the exercises after finishing. Don't. I think the book would actually suffer for that kind of treatment, and you as a reader would be cheated. My advice would be to take the slower path through the book and let it sink in. Each chapter has a theme, even if it is recommended reading or preparation for a ritual. Taking a month to do the exercises may seem slow, but I find it's giving me time to consider the concepts involved on a different level than I have in quite a while.
I've been a practising wiccan for 10 yrs, and I still am enjoying myself with this book. I bought it as part of a reconnection/regrounding exercise, and am not disappointed. There is quite a bit here for non-beginners as well, if it is taken slowly.
My only concern would be that as much as I might like and agree with many of the author's opinions, I would worry that someone who was a very new beginner would perhaps not see that they are just that - opinions. While I like her style and her confidence, I can see beginners who hadn't read other books first might take what she's said as being some kind of absolute truth. (i.e. her opinions on indoor vs outdoor ritual) I would recommend this book be read in connection with other books on the craft - but to be fair, even the author recommends this as part of the exercises of the book. Honestly, I think the author's pull-no-punches style is refreshing, but I can see how some might be bowled over a bit by it. This book isn't for fluff-bunnies.
For beginners who have read a bit already and for old fogies like me who like to see things with eyes anew from time to time. There's a lot here to think about, definitely - enjoy!