So I just finished reading a book about a serial killer. Sigh. There are a lot of books about serial killers out there. In fact, there may be more books about serial killers than there are actual serial killers. The attraction of these villains is obvious—they give an author license to come up with particularly fiendish kinds of murders without having to really work with motives. The serial killer kills because he can, and because he likes it (there are, of course, female serial killers, but there are fewer of them, both in reality and fiction).

In the hands of a skillful writer like Tess Gerritsen or Karen Rose, the serial killer can be both terrifying and oddly compelling. He represents an ultimate threat to the heroine (usually) or the hero (occasionally). Because the serial killer has no particular motivation, he can’t always be anticipated—the detective works on patterns of behavior rather than on any clearcut reasoning on the killer’s part. The killer may in fact be fiendishly clever (post-Hannibal, most of them are), but he’s still not rational. He’s killing for a sexual or psychological thrill, not because he has any kind of coherent plan.

Which is why he’s frequently a bore. I know I’m in the minority here, but I’m just not that into serial killers. Motivation is a great attraction in traditional mysteries and thrillers—why is something happening? What’s behind this murder or set of murders? It’s what animates detectives from Sherlock Holmes to Nero Wolfe. Trying to figure out just what’s going on is fun. But it’s also tough. Devising a plot where the killer kills because of something he needs or because of some quirk in the story is challenging.

Think about what happens when there’s a murder in the “real world.” The first thing we want to know is why. Why did the murderer do it? Was it planned or impulse? Did the murderer and victim know each other? Was there some kind of situation that led to this particular act? Even in this horrific age of mass shootings, we still want to know why a tragedy happened. Was the killer motivated by politics? Did he have a grudge against those he killed? Was he trying to make some kind of insane point?

Motivation obsesses us. But the psychopathic serial killer found in a lot of contemporary thrillers has no motivation to speak of. He just likes killing people. His thinking goes into coming up with nasty ways to dispose of his victims. There is, I suppose, a sort of fascination in that. But it’s not a fascination that holds my interest for long.

So I’ll go on reading serial killer thrillers, but I won’t seek them out. I’d rather spend time trying to unravel the clever plot. I may or may not buy in to the chain of evidence in the end. But at least I’ll have the fun of trying to figure it out.