I'd had this book on my wishlist for months, until I actually saw it in person in my local Waterstone's. It came off my wishlist soon after.
It's written for a very young audience, early-mid teens maybe, with huge print, and lots of needless illustrations. It reads like a teen magazine and not like a 'grown up' craft book. Also, the vast majority of the reconstruction suggestions are horrible and unwearable, ripped in places and safety-pinned together.
If you really want to make your t-shirts into wearable clothes, buy a sewing book and learn the basics first, then experiment with your t-shirts on your own. You'd learn a lot more that way than by buying this book.
However, if you know a 14 year old girl who wants to get into crafting, this may be a good buy.