The warning should be, skip over this book, it kinda sucks and I have plenty of others for you to read. I guess when you release as many books a James Patterson, there are bound to be clunkers every once in a while. Released in 2007, this was his 47th book, one of 6 released that year. I've read the 46 books that were released before this one and going on memory, this is the worst of the batch - only one I can recall not worth reading.
The book is billed as "psychological suspense" but never came off as anything but a story that might work for a cheesy Lifetime movie. None of the characters are strong, none of the devices are used effectively and absolutely nothing is believable about anything in this book.
I think the only redeeming quality of this book is that it is written the way that Patterson writes, so it reads quickly; at least you won't feel like you wasted too much time reading it.