There seems to be a lot of discussion of the appearance, in "Orientation", of the books Turn of the Screw and The Third Policeman, and whether or not they're clues with some relevance or just red herrings. I seem to be one of the few people who have actually read both books, and here's a few thoughts:
Both books are not really "about" what they're "about". Turn of the Screw is putatively about a governess who thinks an evil force of some kind is menancing her wards, while The Third Policeman is putatively about a misguided autodidact who involves himself in a nefarious criminal plot. The real hooks of the books, though, is different: they're entirely about ambiguity and concealed narrative -- that is, an unreliable author who either refuses to make decisions for you, or who withholds information from you.
In Screw, the real question isn't "What will the governess do to protect her charges?"; it's "Is there really an evil force threatening the children, or is the governess just a nut who THINKS there is?". Likewise, and spoiler here for anyone who might want to read this brilliant and hilarious but painfully obscure Irish novel, the big twist of Policeman is that the main character and narrator is, in fact, dead. He dies early on in the novel, and is condemned to a sort of hell where he will pay for his criminal past by reliving various harrowing, confusing or bizarre scenarios over and over.
So what does this mean for "Lost"? The ambiguity angle isn't hard to figure -- it's probably just the writers telling us that it's in our hands to decide if the survivors are really experiencing what they seem to be experiencing, or whether they're crazy/hallucinating/etc. The concealed narrative is harder to figure, and poses a difficult possibility -- that nothing is real, and everything we've seen is some variety of illusion. (I almost hate to consider the possibility, because 99 times out of 100, it's a big let-down when used in fiction; though in The Third Policeman it's actually done quite well.) We've already received many hints that everything that's happened is an illusion, that there is no "real" island:
1. Walt's apparent ability to make things happen with his mind. Did he create the whole island out of thin air? Is everything going on just a product of his bizarre mental powers?
2. Innumerable dream-sequences. Are they all hallucinations-within-a-hallucincation? Has this whole show been the dream of a John Locke, confined to a sick-bed?
3. Sun's question at the end of S1 to Shannon about whether they were all being punished for bad things they did in their lives. Is the island Hell, and is everyone really just being punished in tailor-made ways?
4. The appearance of two novels (I think the only other book we've seen is "Watership Down", which I've also read, but it was when I was 7 or 8 years old, so I don't remember much about it) that deal with ambiguity, with illusion-as-reality, with the notion that various menaces and experiences are nothing more than the illusions of a fevered mind, or of a dead man condemned to Hell. Did everyone on Flight 815 die? Have the whole 20+ episodes been a hallucination seconds before death -- or a fevered dream of someone after death? (At this point, I wouldn't be surprised to see the Scottish novelist Alasdair Gray's book Lanark -- about a man who nearly dies, then wakes up in a dystopain city where he has numerous bizarre adventures, when in fact he really DID die and is in a sort of Hell -- makes an appearance. It's the first thing I though of when Sun floated her punishment theory.)
At this point, there's more than enough out there to suggest that everything on the island is unreal -- a dream, a hallucination, a punishment of the afterlife. Of course, that could be nothing but red herrings, since the writers have apparently officially denied that all the passengers are dead and the show is little more than their dying thoughts. So maybe this whole post is moot. But it's what I been thinkin' about, so there it is for what it's worth. Which is, like all other speculation about the show, nothing.