Have you ever sat in front of the TV or in a movie theater watching a thriller, squinting through your fingers and wanting to leave or shut the TV off?  Or stayed up until three A.M. to finish a book, because it had you on the edge of your seat.  You had the ability to walk away, shut the T.V. off or shut the book, but didn't.   The game between you and the villain began with that first impulse to stop the story.  Who will win, will you finish the story?

The reason for this is the anticipation.  A good writer doesn't use gore to pump up the thrill.  Much like the best love scenes the impact is in the emotions and not the physical action.  I've often gone back and read a love scene that struck me as being incredibly strong and wondered how the author could sustain it through eight or ten pages, only to find the physical portion of the love scene to be one or two pages long.  The emotional build up and anticipation was what made the scene so strong.   

There are two key elements that keep pages turning.  First, the villain must take something comforting or safe to you then turn it threatening and dangerous.  For example, a hospital that is associated with a place to go for help and healing could have a hidden ward where the villain tortures the victims.  A camp that you've always gone to as a quiet retreat to escape daily stress becomes the murder scene of a loved one.

By doing this you begin to second-guess what's around the next corner.  It's the not knowing that hooks you.  You think you know what's going to happen, you know more than the characters, but not as much as the villain and that's the key. 

The second element that comes into play is the villain's mind; it's a complicated thing.  It has a motive, whether it makes sense to you or not, it makes sense to them.  The villain plans everything out and the end will always justify the means.  Innocent people don't matter, they're only pawns on the chessboard.

The game begins in the first scene and it's a race between the reader and the villain to see if you can figure them out before they show their final moves to you.  They let you in on parts of their life and inside their twisted mind, while keeping you on edge, scared for the hero and heroine.  You try to think like them, but you can't because you're sane. 

To me a great thriller is one where I've understood and empathized with the villain's motive.  I know what they're doing is wrong and abhor it, but in a twisted way I almost root for them.  When I believe the villain to this depth, it's a book I can't put down.  Pass the popcorn, please.