I'm a big Patterson fan. I've liked everything of his that I've read so far with the exception of 'The Lake House' and it appears that this will have to be one of those books that I didn't really like all that much. 
 'You've Been Warned' follows the actions of selfish photographer/nanny Kristin Burns as she has an affair with the father of the children she takes care of. Soon things start to unravel as strange things happen and she starts hearing this tune she can't get out of her head. She also begins to dream of 4 deaths in a hotel at the same time. 
 'You've Been Warned' is quite possibly the most mediocre book I've ever read by Patterson. The plotline would be intriguing, but the delivery just falls short of expectations. I'd be willing to put up with this if it wasn't for the unlikable main character of Kristin. Not only does she have an affair, but she stalks him whenever she gets a chance & tries to insert herself into the children's lives in their mother's place. Then she gives herself excuses as to why her actions are perfectly ok, excuses that are pretty much delusional. Maybe he was trying to display how delusional & selfish she is, but by doing so he turned her into a character that I care nothing about. When the end of the book comes (and the ending is ambiguous as to her fate) I found that I didn't care if she lived or died--which is the worst fate for a book, that you just don't care how it ended.