The structure of a story is its bones – or rather, it’s the way those bones are presented to the reader, the way things are organized and the patterns they make. Like bones, there are large ones and tiny ones; chains of things that fit together to provide flexibility and long solid ones for support. Also like bones, there are a multitude of possible workable arrangements, from birds to fish to mammals. Finally, like bones, the structure of the story is usually hidden under all the other stuff that’s going on…and if it isn’t, if it’s obviously poking out somewhere, that almost always means something is seriously wrong.
The most common structure is the linear, chronological one: the author presents the events of the story to the reader in the order they happen to the viewpoint character. Sometimes, that means that the POV character (and the reader) find out about something long after it actually happened, but from where the POV is standing, that’s when they found out, so that’s when the reader finds out.
This is the workhorse of structure, used by everything from fairy tales to Shakespeare and Beowulf. The author has plenty of decisions to make: Was the tiara stolen before the murder, or after? Did the queen set the fire to cover her escape, or did she wake up smelling smoke and run from an already-existing fire? But once those decisions are made, the author doesn’t have to decide anything more about the order to present them in; the linear, chronological structure takes care of that for her.
Linearity doesn’t necessarily mean single-viewpoint. Multiple-viewpoint novels are often fairly linear; the author switches from one POV to another, but the events keep marching steadily forward. Every so often, there’s a slight jog back in time, as we catch up with what Jennifer was busy doing while George was having lunch with the villain in the prior scene, but for the most part things progress from A to B to C in the order they happen; it’s just that the reader gets to see what Lisa was doing as she does it, instead of hearing about it later when George finds out about it.
Non-linear structures cover everything else, and require a lot more decisions on the part of the writer, because not only does she have to decide what order things happen in, she then has to decide what order to present them in. Does she want the shock of showing the protagonist’s attempt to steal the tiara, and then go back to describe the events leading up to it, or would she rather have the long, slow buildup of events culminating in the theft?
There are two basic approaches to non-linear structures: the kind where there is a fixed pattern to the scenes shown (as in Steven Brust’s Taltos, where each chapter opens with a flash-forward scene that’s part of the spell the narrator is casting at the end of the book, then has four sections that alternate between the narrator’s “present” [which slowly converges on the spell] and his biography-to-date; the sequence doesn’t vary), and the kind that’s more like free verse, where the pattern of the scenes is less clear, more flexible, or random.
Ian M. Banks The Use of Weapons is another example of a nonlinear pattern: one set of chapters moves forward in time chronologically from Chapter One; the alternate chapters move backward in time, and are numbered in reverse. Roger Zelazny’s Roadmarks also plays with structure and chronology in alternate chapters as the characters travel along a road through time, and within chapters as the reader sees the cliffhanger problem and then sees how they got out of the last one and into this one.
Non-linear patterns don’t have to be based on chronology or reverse chronology. Scenes can be ordered according to their emotional weight, or the pattern may be one of style (one short story I ran across alternated scenelets that were total narrative summary, standard dramatization, and nearly pure dialog/talking heads). They can circle or spiral back to a place or time or event or emotion repeatedly. There are lots of patterns, and some of them can be used in conjunction with the common linear one, too.
A non-linear story that has no pattern to the scenes – one that’s random, where a flashback is thrown in whenever and wherever it seems to be needed – is surprisingly difficult. You would think that being required to repeat a sequence of scenes would be more limiting than being able to do whatever you want, whenever you want, but without a structure behind one’s choices, it is a lot harder to be sure that a flashback or flashforward is really needed (as opposed to simply being the easy way out for the author, which nearly always ends up looking sloppy).
Structure is fun to mess around with (at least I think it is), but there are times when a non-traditional, non-linear structure really makes a difference. The “parallel scenes” technique, for instance, where the author takes a straightforward story A-B-C-D-E-F-G, and splits it in two, opening with D (an exciting predicament), then flashing back to A, continuing on to E, then back to B, so that the story is presented as D/A-E/B-F/C-G. This is particularly useful when the first few chronological scenes (ABC) contain critical but not very dramatic information, or when C is a climax of revelation that the author wants to occur close to the action climax at G, instead of half a book away.
On the other hand, there are plenty of excellent writers who have never strayed from the straightforward linear structure. I think it is useful to be aware of the possibilities, but if you have no interest in actually writing them and/or no story ideas that would be well-suited by a non-linear approach, then there’s no reason to push yourself in that direction. And for most of us, non-linear storytelling is a stretch, and best done after getting a gut-level feel for how the more common linear structure works. For those others, the ones for whom non-linearity comes naturally and it’s the linear mode that is hard, well, do the same thing in reverse – that is, really master what you start out with, and then stretch into the tricky stuff.