“Two hundred European cities have bus links with Frankfurt”

Let’s say you’re reading a novel, perhaps a thriller, and while you wouldn’t say it’s a great book, you’re reasonably engaged by the plot and characters. The story is clocking along nicely, the author’s prose is clean and unobtrusive, and suddenly you’re brought up short by something like this:

He was sitting all alone in the enormous cabin of a Falcon 2000EX corporate jet as it bounced its way through turbulence. In the background, the dual Pratt & Whitney engines hummed evenly.

Hold on. What do those Pratt & Whitney engines have to do with anything? Is this a novel or an aircraft catalog? Well, it’s neither, at least not at the moment: rather, it’s an instance of a novelist being reluctant to part with a laboriously acquired piece of research. Suspense novelists are especially guilty of this sort of thing—the above example is from Dan Brown’s The Lost Symbol, admittedly not the most original target in the world—but it’s something that every writer needs to beware: the temptation to overload one’s fiction with factual detail, especially detail that was the result of a long and painful research process.

This tendency is easy to understand in historical and science fiction, in which so much energy has gone into researching a story set in another time and place, but it’s less obvious why it should also be so common in thrillers, which in other respects have become ever more streamlined. Anthony Lane, in an amusing article on the top ten books on the New York Times bestseller list of May 15, 1994, quotes a sentence from Allan Folsom’s thriller The Day After Tomorrow (the one about the Frankfurt bus lines), which he claims is the most boring clause in any of the books he’s read for his essay. He then says:

The odd thing about pedantry, however, is that it can’t be trusted. Many of the writers on this list are under the impression that if they do the factual spadework, the fiction will dig itself in and hunker down, solid and secure. The effect, unfortunately, is quite the opposite. It suggests that the writers are hanging on for grim life to what they know for fear of unleashing what they don’t know; they are frightened, in other words, of their own imagination…When Flaubert studied ancient Carthage for Salammbô, or the particulars of medieval falconry for “The Legend of St. Julien Hospitalier,” he was furnishing and feathering a world that had already taken shape within his mind; when Allan Folsom looks at bus timetables, his book just gets a little longer.

True enough. Lane is mistaken, though, when he blames this tendency, elsewhere in his article, on the work of James Michener, which consists of “gathering more research than any book could possibly need, then refusing to jettison a particle of it for the sake of dramatic form.” Michener is probably to blame for such excesses in historical fiction, but as far as thrillers are concerned, there’s another, more relevant culprit: Frederick Forsyth. Much of the pleasure of The Day of the Jackal (which Lane elsewhere claims to read once a year) comes from Forsyth’s expertise, real or cunningly feigned, in such matters as identity theft and the construction of an assassin’s rifle, which makes the less plausible elements of his novel all the more convincing. He’s so good at this, in fact, that legions of inferior writers have been seduced by his example. (Even Forsyth himself, in his later novels, isn’t entirely immune.)

Here, then, is the novelist’s dilemma: an appropriate amount of research will lure readers into the fictional dream, but too much will yank them out. So what’s a writer to do? The answer here, as in most other places, is that good habits of writing in general will trim away the worst of these particular excesses. For instance, Stephen King’s invaluable advice to cut all your drafts by ten percent applies twice as much to expository or factual passages. We haven’t discussed point of view yet, but by restricting each scene to the point of view of a particular character, you’re less likely to introduce extraneous information. And the endless labor of rereading, editing, and revision, once time has given you sufficient detachment from your own work, will gradually alert you to places where the research has begun to interfere with the underlying story.

There’s another place where excessive research can also be dangerous, and that’s in the writing process itself. Nearly every novel requires some degree of background material, but how much is too much? It’s always hard to say when research turns into procrastination, but here’s my own rule of thumb: two or three months of research is probably enough for the beginning of any project. Later on, you can always take a break to do more, and should certainly go back and check your facts once the novel is done, but any more than three months at the start, and you risk losing the momentum that encouraged you to write the novel in the first place. And once that momentum is gone, not even a Pratt & Whitney engine will get it back.