In Medias Res

Classical epic notoriously did not begin at the beginning, go to the end, and then stop. It is not just that the Odyssey and the Aeneid begin partway through the overall arc of what they are telling; shortly after they begin, they allow the hero to narrate the beginning part of the story (in Homer's case, in a sizeable inset with its own inset: Odysseus is nine years into a ten-year story arc at the time; and the actual retelling of the fall of Troy is a further inset narration by an aoidos).

(The Iliad is more linear, if one wants to consider it the story of the wrath of Achilles; if its matter is taken to be that of the Trojan war as a whole, it also begins nearly at the end. But in place of an inset narrative, it merely makes references backwards to a story its audience knew well - much as it throws in foreshadowings of the death and burial of Achilles and the end of the Trojan War despite its formal end with the funeral games for Hector, tamer of horses.)

Linear narrative is almost as old - visible in the Homeric Hymns, for example; and the Greek novel, later on, tends towards linear narration (but with important backstory). The mediaeval romance uses interlaced narratives, but with linear narrative - straight past to future - per strand.

(Linear is probably a misnomer. Most narratives jump, unless they deliberately, obsessively hew to the tightest possible form of the Aristotelian unities; so it's more like a series of shorter and longer dashes. But it's the term I'm going to use for simplicity's sake.)

Pope's narratives are linear, as are Byron's:

Most epic poets plunge "in medias res"
     (Horace makes this the heroic turnpike road),
And then your hero tells, whene'er you please,
     What went before—by way of episode,
While seated after dinner at his ease,
     Beside his mistress in some soft abode,
Palace, or garden, paradise, or cavern,
Which serves the happy couple for a tavern.
 
That is the usual method, but not mine—
 My way is to begin with the beginning;
The regularity of my design
     Forbids all wandering as the worst of sinning...

And many if not most 18th and 19th Century novels are also linear: Fielding, Austen, Eliot, James, though Emily Bronte has a nice example of an inset story beginning towards its end, and Conrad makes good use of nested narratives, though not of beginning in the middle of things.

These days, the odds are good that if you pick up a novel at random - particularly a genre novel at random - it will be a linear plot. Even the massively interlaced narrative in A Song of Ice and Fire moves forward steadily, with only occasional glances backward. Seveneves buries its first two thirds as an epic replayed in the background in the final third, but it reaches that frame only in linear order. (Stephenson does cut back and forth between present and past in Cryptonomicon, though the book does begin at the beginning, if one disregards the preface. The very beginning: "Let's set the existence-of-God issue aside for a later volume, and just stipulate that in some way, self-replicating organisms came into existence on this planet..." The Baroque Cycle shifts between the time of George I and that of Charles II, and its second volume moves in alternating blocks.) And most authors are more conventional than Martin and Stephenson. (Except for Brust. The Vladiad is an impressive tour-de-force in variant narrative structures.) Erikson does begin The Gardens of the Moon in medias res, and the series as a whole moves backwards and forwards in time, to a degree.

I had been thinking about this having just finished Le Carré's Tinker, Tailor, Soldier, Spy. Not only is the bulk of the book told in flashbacks - some Smiley's memories, some people talking to Smiley, some documentary - but on reflection it's clear how dull and disconnected it would be had Le Carré decided to tell the story in a linear manner.

It's not that Le Carré generally avoids linear narrative. The Spy Who Came In From The Cold may return physically to where it began, but chronologically it moves steadily forward.

(Sometimes a story is all flashback. Consider Sunset Boulevard).

What is perhaps worth pointing out is how this sort of narrative reduces, if it does not quite extinguish, a sizeable chunk of the normal tension based on plot. There is always possible tension regarding the ultimate resolution of the story, but the pattern of stopping the narrative to go back reduces the tension during the retelling of the first part of the story - no question of what's going to happen to Palinurus - and halts sny forward motion of the plot for a time.

What it loses in narrative drive it has to make up in other forms of interest. It is worth noting that the one genre to use the form consistently is the mystery novel: although there are many mysteries which provide a slow build to the crime followed by a gradual unravelling, many, especially those with professional or at least frequently consulted detectives begin with the crime - usually a murder - and gradually uncover the backstory as the investigation moves into the future. (Thus clearly is an influence on TTSP, though the proportion of flashback to actual investigation skews away from the detective novel.)