This book contains some information helpful to my line of work, but there's also a good deal of misinformation, disinformation, and some outright lycanthrope propaganda. This might not be intentional on the part of the authors, but they made the mistake of relying too much on infected sources; failing to at least interview a handful of credible werewolf hunters makes this quite one-sided.
I get it. It's a guide for the newly bitten. But human readers should be aware that this does not paint a comprehensive or appropriately grim image of the curse of lycanthropy. The blight of the bitten upon human society.
And I haven't even mentioned the absurd notion that lycanthropes actually double in weight when they transform. This is, quite simply, scientifically impossible for biological animals. Pure fiction. Mass does not spontaneously generate. The biters spread this disinformation because it makes them sound scarier—makes many a skilled hunter question whether he can take on such a monster. Of course, lycanthropes do SEEM to grow when they change, but this is mainly due to the long, bristling fur. Ever shave a husky or other long-haired dog? Yeah. Quite a difference.
The shifting of body proportions during a transformation also accounts for some of the perceived increase in size. A werewolf can, of course, quickly turn all avaliable stomach contents and stored fat into muscle (you will never encounter an obese lycanthrope), but turning partially digested beef into a similar amount of lupine sinew is a transference of weight—not an increase.
All that being said, a werewolf usually does end up weighing more than s/he weighed as a "human," but only through normal means: eating. And the "human" form will carry whatever new weight the beast amassed.
Anyway, the book is a mixed bag. I can't recommend any such pro-howler material, but I did come away with some new information that seems credible.
I usually write fiction, but I used to be a journalist, and I'm currently writing a book about my own experiences with lycanthropes. Release date is sometime next year. Follow me for more.