I think that Dean Koontz is the best suspense author. He knows how to keep everything from the reader until the story is towards the end. You usually wont know what is going happen until it actually happens. It is amazing how he does this, and must take a lot of time to draw it out and then write it all down.
Dean Koontz first uses mystery in the main characters life. In the beginning we find out that the main character losses consciousness for seven minutes and does not remember at all what happen except for the lines " I need, I need, I need, I need," on his tape recorder. This is a big mystery to the reader and for the main character because he has no idea what happened to him and neither does the reader. There is also the part of the stranger how is a mystery to everyone. This is a man who does what he is programmed to do what he is told. You have no idea who he is and where he from, but all we know is that he looks just like the main character. Which is a mystery and asks the questions how? In the book there is a part that says, " Daddy wasn't Daddy. He had Daddy's blue eyes, Daddy's dark brown hair, he sounded like Daddy; he was a dead-ringer for the Martin Stillwater pictured on the dust jackets of his books," . Which mean that when the main character's daughters were to see him they would think he was there father. It is also a mystery that you don't really know if the stranger was the real Martin Stillwater or if he was just his twin. There is a story that the main character wrote for his daughters entitled "Santa's Evil Twin." This is very weird to the reader because the story is somewhat based on what happens to the main character and his family, and that the main character doesn't realize the connection until the end.
Also there is suspense in the book and that is when we find out that the stranger will not leave the main character and his family alone until he got his life back for the main character.