Disappearance at Devil's rock

Last year, Paul Tremblay's A Head Full of Ghosts was viewed by many as the best horror novel of the year. While others may disagree, I don't think Disappearance at Devil's Rock is quite as good, but it's still a very good book.  I think this has to do with the subject matter, which is the disappearance of a child. This is something that parents will find extremely horrifying, but as a single guy, it doesn't really do as much for me.

The book is about a mother whose teenage son vanishes from a local park while he's on a late-night hike with some friends. Soon strange things start happening. The mother sees a shadowy vision of her son. His diary pages mysteriously appear in the living room. A dark figure  is spotted peeping into neighborhood windows.

My main gripe is that I thought the book started off a little slow, and didn't really pick up until about 1/4 of the way into the book when the mother discovered that her son and his friends had been secretly meeting a man called Arnold. At that point I had a hard time putting the book down. I don't know that this book will be my favorite of the year, but its certainly going to be in the top 10.