Having taken a close look at some pieces of detective fiction, the Noir writing style, and various episodes of CSI, I have arrived at three initial conclusions. The first is that Mysteries usually challenge the reader to solve them. The second is that atmosphere seems to have become more important for Mysteries in recent years.
The third, and probably the most remarkable, is that a Mystery seems to become far more interesting when it deals with a very unlikely crime or a very intractable situation.
The latter idea does not come as a surprise. Suppose that you're a witness at two different crime scenes: Victim A lies dead in the middle of a wooden floor with a bullet in his chest, while Victim B lies dead in the bathtub, wearing a skintight black leather suit with pink polka dots and clutching a rubber chicken in his left hand. Which of the two cases would immediately pique your curiosity?
This, I think, is why shows like CSI get some very good ratings. We don't watch these shows because we're interested in Grissom's entomology skills, or Caine's intensity, or Taylor's love life. We watch these shows because some writer decides to present us with a very improbable situation at the start, then goes through the motion of telling us exactly what happened.
What happened? is one of those questions that will concern us the most, regardless of who we are, or what we have to do with the situation in the first place. We are compelled to get an answer and resolve our curiosity. Failing that, we can do nothing but gawk at the crime scene, in the hope that somebody's nice enough to explain things to us.
This, I think, is the primary factor in an interesting Mystery. Good Mystery fiction has to get the reader asking questions about the story: What happened? Who did it? Who's involved? Why did it take place? And for goodness' sakes, what does the rubber chicken have to do with all this?
Mysteries are an exercise in the intractable situation and the logical conclusion. They allow us to follow the clues and attempt to unravel everything ourselves; We may or may not be able to do this depending on how well the story is written, but we do end up greatly empathizing with the dapper sleuth, the dilettante scholar, or the hard-boiled detective who is tasked to tie up all the loose ends.
I find this to be a great hook, mind you. It's hard enough to grab a reader's attention with an ordinary story, but present him with an unexpected murder in a seemingly impossible situation and he'll inevitably wonder just how the whole thing took place. And when he finally relishes the last words and closes the book on the Mystery, he's going to feel very satisfied at having sated his own personal curiosity. This, despite the fact that he had absolutely nothing to do with the crime or its proponents beyond turning the pages.
It's funny, somehow. Reading a Mystery is therefore something like staring at the scene of an accident, or rushing outside to watch the fire engines go by. We can't help ourselves -- we just have to know what happened. Yes, we know perfectly well what the sirens mean; But we still have to know what the sirens mean.
I'll try to adopt this approach the next time I head in this direction. At best, I could write a rip-roaring exposition of some twisted conspiratorial scenario. At worst, I suppose that I would have written a very odd crime scene for the books.
Whatever the case, I figure that the compulsion is there. People are just curious, I think. We just really want to know what happened, how events came to such a conclusion, and who was unlucky enough to go down for the count. It's human nature, yes. And it's a mystery.