It’s taken me a long time to get back to this one. But, okay: Sci-Fi tie-in fiction.

For the record, I’ve got nothing against the authors of tie-in fiction. Hey, a job’s a job. I won’t even go so far as to say that tie-in fiction is generally bad or generally good, because I haven’t read enough of it to make that case on a general basis. Okay, yes, there are a few specific examples of a couple of Star Wars and Star Trek books that I didn’t like, but I’m not going to name names because, frankly, I don’t think it was the writers’ fault that I didn’t like their work.

Actually, there’s one sliver of the sci-fi tie-in market on which I do feel somewhat qualified to speak: the Doctor Who franchise. Because I have actually read a lot of those books.

I enjoy them on a certain level, otherwise I wouldn’t bother with them. And yet, the quality really varies. Again, not to name names, because I respect the writers too much to call them out for something I don’t think is their own fault. Because, in the end, I think there’s a structural issue that tie-in fiction has that original fiction doesn’t have to deal with as often.

It hit me as I was listening to a To The Best of Our Knowledge podcast on Sherlock Holmes. As a preface to some interviews with modern writers who have written their own Sherlock Holmes stories, the host said something like about how the character might have been created by Arthur Conan Doyle, but he’s always belonged to the fans. Which I thought was a phenomenon of a more recent vintage. But, of course, we’ve been taking ownership of our fantasies, whatever their origins, since the days of campfire tales of gods and kings. Which is the key to why tie-in fiction has some problems that are often misinterpreted as being related to the quality of the writing involved. But, really, the problems are not (usually) with the actual prose on the page, but with the nature of how we share our fantasies.

Look at it this way: When you pick up a work of original fiction — Larry Niven’s Ringworld, for example — you’re meeting a cast of characters for the first time. All you know about Louis Wu, or Speaker-to-Animals, or Teela Brown (to stick with our example) is what the author tells you about them. With his help, you form a picture of them in your mind, and (since the author knows what he’s doing) they act in ways that makes sense for the characters, throughout the book.

This is not usually the case with tie-in fiction. I pretty much know what the Doctor’s character is, and how he’d react to an arbitrary set of situations — at least, I think that I do.

And that’s kind of a problem. Because the model of the Doctor and his companions that I have in my head is likely not quite the same as yours, or that of the writers who have created all those tie-in novels. More to the point, after listening to a couple of American authors speak confidently about what Sherlock Holmes would think or like or do, in that podcast I mentioned earlier, I realized that I’ve got hundreds of these little character algorithms in my head that tell me how characters from various movies, TV shows, books, and comics should act. They’re all highly individual to me, these algorithms, and they don’t match what tie-in writers have in mind.

I’m not right about my interpretations of how fictional characters would think or talk or act, of course. What’s right when it comes to the emotional life of an imaginary nine-foot tall walking carpet? But, I still have these things rattling around my head — for good or bad. So, when I read tie-in fiction that does not accord with the equations of my Fan Processing Unit™, the result is not smooth, quiet operation, but rather a clunking noise that hurts my head.

And how is any of this the writers’ fault? If they weren’t generating headaches in my own personal cranium, it’d only be somebody else’s that’d wind up getting rattled. You can’t win them all.

Of course, there are some tie-in writers who are not at all gifted at using the written word to generate pictures in people’s minds. But if you combine mediocrity with clashing character models, it makes the lackluster prose seem worse than it is. It generates rage, sometimes. And, hey, Cormac McCarthy himself could write the most gut-wrenchingly epic Star Trek noel of all time, but it would still grind my gears if he got Kirk all wrong, as I see the character. I understand the reaction. But that doesn’t mean it’s justified.

So beyond — or, rather, parallel to — Scalzi’s excellent points about why people who write for a living would be willing to involve themselves with tie-in fiction (money and creative opportunity, mostly), also consider this: Many tie-in authors are fans, and they’ve got as much right to think they understand these shared characters and universes as anybody else.

We don’t always agree. That’s what fandom is for.