I probably would have read this book anyway, because I read all of her other vampire-world books (I can't pronounce the name of her other series so I really can't even imagine trying to read it), but Amelia came to our local Toadstool Bookshop and what she said about this book really intrigued me.
She got her undergraduate degree in psychology (like me) and the psychological aspects of the story - a girl who has spent her life in and out of mental hospitals due to hallucinations and disassociative episodes... but is she really crazy, or is there a supernatural thing going on? - really appealed to me. Strangely enough, the ending of this reminded me a bit of Sybil. Amelia had mentioned how her editor made her tone down a lot of the psychological explanations in the story, but I found those areas really interesting.
Amelia also talked about how the "Den of Shadows" series was named this after they were all published, so although this book might not be marketed as a "Den of Shadows" book, it is still in that same world. If you've read any of those books, you'd know that they are all pretty "stand-alone" rather than a series, so don't feel that you need to read all of them in order to make sense. There are characters that often pop up in more than one book, but you could read this without the others. Of course, I read them all in order...
I also should mention that this is a pretty quick read - not quite as fast as In the Forests of the Night, which I believe she said was 25,000 words (or half a novel, in Nanowrimo terms, and yes, she is a Nanowrimer too, which just makes her more awesome).