Some long novels, Martin Amis once noted, are really short novels that happen to go on for a long time (indeed, he thinks "most long novels are this kind of long novel, where writers routinely devastate acres of woodland for their spy thrillers, space operas, family sagas and so on"). On the other hand some long novels that are long "because they have to be, earning their amplitude by the complexity of the demands they make on writer and reader alike." He doesn't talk about a third type: the short novel that is paradoxically a long novel. I don't mean a condensed book, or a fragment that hints at greatness; I mean that rare item, a book that folds magnitude into hidden dimensions within its narrow one-eighty-pages.

Philip Dick wrote those sorts of novels. A sense of something hidden, something underground and flourishing in the interstices, like bluebells growing in the cracks of the pavement (or blooms of mors ontologica in amongst the corn) energises his fiction. It's this something that has kept his books alive when better written, better structured and better plotted novels have fallen into obscurity around them. Which is to say that critics can, and do, point to evidence of hasty writing in Dick's works, patches of ragged or inexpressive prose, or occasional addled-head-ness in most of his books (he took a whole bunch of drugs, after all). But even with all that, or conceivably because of that there is a quality that PKD's books possess that few other books, in or out of genre, can match. It is a sort of fascinating aesthetic uncleanness, resonant and enduring. More polish would have rubbed that quality away.

Dick's reputation has, of course, followed a strange path: from unconsidered pulp outsider to American Literary Name, or even canonical figure—a rather dispiriting trajectory, actually, that owes much to his popularity with the Big Business of Hollywood production. Dick's acceptance by the establishment has reached a new milestone with his inclusion in the handsome black-liveried Library of America edition, where he can now stand alongside Melville and Whitman, Henry James and Philip Roth. But it is always refreshing to return to Philip Dick's actual prose and remember how poorly the label "great American writer" fits him, and how superbly saving that fact is.

So it's nice to hold this volume in my hands; as handsome and compact as any Library of America issue (and as expensive: $35). It contains, as its subtitle says, "four novels of the 1960s," chosen and edited by Jonathan Lethem: The Man in the High Castle (1962), The Three Stigmata of Palmer Eldritch (1965), Do Androids Dream of Electric Sheep (1968) and Ubik (1969). There's no introduction, that not being LoA house style; but there is a detailed timeline of PKD's life, which makes curiously disheartening reading, and there are endnotes that suggest (nine pages of detailed notes for High Castle, but only a third of a page—eight notes in total—for the whole of Palmer Eldritch) that some novels engaged Lethem more than others. I suppose we might argue that High Castle needs more annotation than Eldritch, what with all those reference to WW2 history and the like; but in their own ways Eldritch, and Ubik (covered in a mere fourteen endnotes) are just as baffling to a reader unfamiliar with the 60s. Best of all is the opportunity simply to reread four novels from Dick's great decade. PKD's books go down better when you munch a whole lot of them in a short space. He's a writer to gobble, not to sip and savour.

The Man in the High Castle occupies an unusual place in the PKD oeuvre because it was the only one of his novels to win a major award in his lifetime (it won the Hugo for Best Novel in 1963); or to be more precise, it occupies an unusual place because of what that fact says about the book. It says it's a book liable to find approbation from regular SF fans. It says it works cannily through an ingenious premise, that it's well-written; tightly plotted, that it construes engaging characters via good and eloquent detail from a properly built-world. Which is a long-way-round of saying that it is uncharacteristic Dick, and rereading it in this new edition (rereading it, I think, for the fourth time) I found that its very polish, its various evidences of craft, alienated me somewhat from the book. Of the four novels collected here it seems to me the least Dickesque, and so the least worthwhile.

High Castle is an example of Hitler-wins alternate history; set in a 1960s in which the USA has been divided east and west between Nazi Germany and Imperial Japan. Frank Frink ekes a living making jewelry and faking antique collectables, an occupation that enables Dick to highlight the slippery problem of "authenticity," of what Walter Benjamin called the "aura" (a term that winkles its way into novel, for instance p. 57), inherent in the whole premise of an alternate history. Frink's ex-wife Juliana falls in with an Italian ex-soldier, but like most things in this novel he too is a fake, or more specifically his Italian identity is a disguise; in reality he is a Swiss Nazi assassin. There is a very readable and efficiently-handled thriller plot, to do with microdots and the secret sinister "Operation Dandelion" to start World War III and nuke Japan. But it's hard to shake a sense of something not there. We don't need Dick to supply us with competent alt-historical thrillers; the writerly world is full of middling writers who can do that, books like Deighton's SS-GB (1978) or Harris's Fatherland (1992). Dick has precedence on those two authors, of course; but he can't claim to have invented the "Hitler Wins" sub-genre (Clute and Nicholls list ten antecedents, and that's just with Hitler; which is to say, not counting a mini-masterpiece like Ward Moore's Bring the Jubilee from 1953). What Dick can give us is a profound creative distortion, and the slightly self-conscious writerly polish of High Castle doesn't capture this. It is a well-handled short novel that feels like a well-handled short novel. Dick's best books are short novels that feel like they contain enormities.

One feature of the novel that escapes these criticisms, I'd say, is the title character; a marginal figure, plot-wise, but crucial in other ways. The man's name is Hawthorne Abendsen, and his High Castle is a house in Colorado. Guided by the I-Ching Abendsen has written a novel called The Grasshopper Lies Heavy: an alternate-history science fiction tale set in a world in which the Allies, not the Nazis, won the second world war. Dick, in a deft touch, makes plain that this alt-history is not the same as our one (in it the British liberated Berlin and put Hitler on trial, for instance), and the existential uncertainty it entails could, perhaps, have troubled the smooth surface of the rest of the novel a little more. At the end of the book Juliana finally meets Abendsen to ask metaphysical questions about the nature of his novel, and through it of fiction as a whole, but his answers are unilluminating, except in one respect. "To Juliana [Hawthorne] said: 'You have an—unnatural mind. Are you aware of that?'" (p. 226). It's as if all the naïf-metafictional pre-postmodernism of the bulk of the novel has been a kind of misdirection, so much so that we can almost miss how important this statement is to Dick's aesthetic; how self-contradictory, or monstrous, it would be to say to somebody "you have a natural mind" in Dick's cosmos.

The Three Stigmata of Palmer Eldritch is as hectic and ragged a book as any Dick wrote, and is consequently much more dream-haunting and powerful than High Castle. It folds a muddle of different ideas together: a dystopic future-world from which people escape into childish games with dolls, illicitly enhanced by drugs; a programme to fastforward human evolution; a messiah figure returning from Proxima Centauri who might be a malign alien. But its loose ends tangle creatively with its core conceits. (Why is Leo Bulero, supposedly an übermensch "evolved" human, so simple-minded and deliberate? How exactly has Edritch managed to travel to and from Proxima Centurai so rapidly? Why do the Can-D users need the Barbie-and-Ken-esque "Perky Pat" and "Walt" dolls to orchestrate their fantasy?—Dick had been inspired by watching his kids playing with such dolls, noticing how thoroughly absorbed in their play they became; but that was precisely play, and has no need of drugs; drug-addicts on the other hand have no need of toys to enable their highs; that's what the drugs are for. Dick's "Days of Perky Pat" combination conceit falls between the two stools. That's not to say, of course, that it doesn't, somehow, weirdly, work ...)

This novel is about many things, not least a sort of consensual-reality accessed via this "Can-D" drug, or an alternate pharmakon, seemingly alien in provenance, called Chew-Z. There is something sacramental about this, although the symbolism is never heavy-handed. It's possible that the conceit looks ramshackle to modern eyes: we might, for instance, say that we are more likely to be persuaded by an electrocephalic mass-consensual reality, like the Wachowski's Matrix: but even then, we recall, entry was effected via a red pill, and food remains a semiological focus throughout the film. Perhaps this bespeaks the oral, rather than anal, bias of SF's imaginative fantasy: we might, for instance, wonder why the SF-loving Comic Book Store Guy in The Simpsons is quite so fat ... "It's an oral thing," Dick's Leo Bulero notes (p.392). In VALIS (1981) Dick made it clear he knew what the German word for fat was. He was himself, of course, a fairly slim man.

Indeed, there is something lean and hungry about Dick's fiction. Food is rarely described in his novels; family meals, or feasts, never. (Drinking is a different matter.) It's an intriguing absence, and has to do, I think, with PKD's suspicion about possession, something he viewed as equally desirable and unachievable. When we eat something we make it unambiguously ours. You and I may bicker over who owns this chocolate biscuit, but once I wolf it down into my belly the debate it over. This is one reason why the pleasures of eating and drinking retain their childish intensity; that portion of our lives when possessing things, and not letting others get their hands on them, can be so vitally important. But it is at the very heart of Dick's vision that things we assume are ours are rarely, if ever, so; not external goods (the material commodities of Ubik), but not even the intimate parts of our own bodies, or minds.

Descartes, famously, searching for one thing that he could absolutely and certainly call his own, lighted joyfully on the cogito ergo sum. It something he was sure no malicious demon could take away from him. But Dick, famously, is an anti-Descartes. He approaches "I think therefore I am" with the devastating and brilliant woah: why do you assume that the thoughts in your head are yours? It's an index to the centrality of the Cogito to Western thought as a metaphysical cornerstone, or guarantee, just how unsettling this brilliant, penetrating question can be.

The punch of Palmer Eldritch is, in the end, the nightmare of being trapped in somebody else's imaginary world. It reflects upon the nature of literature; the horror of finding oneself a slave to the artist or writer; the sacrament of art that, by entering the body, locks us in. That existential claustrophobia, something he captured as expertly as any twentieth-century writer (and which was one of the great themes of twentieth-century art) finds particularly resonant expression in Do Androids Dream. Rick Deckard, the android-hunter, is surrounded by inauthenticity; his animals are fake; his wife's emotions are decanted into her from a machine; he can't be sure if the people around him are actual or artificial; the god of his religion is nothing more than an elderly actor performing a role.

It's conventional to observe how very different the movie adaptation, Blade Runner, is to the original novel, a position that can perhaps be overstated. But as far as this realization of existential claustrophobia goes it holds true. Ridley Scott, trying to find a visual correlative for the novel's sense of claustrophobia, rendered it literally: all those choking streets, crowds, dark, narrow spaces. Dick's instincts were cleverer: his hemmed-in characters exist, counter-intuitively but rightly, in the echoing, enormous, empty spaces of a mostly abandoned planet. Scott's replicants, with time's winged chariot hurrying near behind them, are pressured to act in the desperate and cruel ways they do. Dick's androids, on the other hand, exist in a weirdly flattened, opened-out world, where vacancy and spaciousness is an externalization of a much more horrifying open-ended moral possibility, a universe in which we can do anything, good or bad, without sanction or support.

Another thing the movie could find no space for is the book's weird and wonderfully dislocating faux-religion Mercerism. It occupies a good deal of the novel, centered on its pointless mystery-that-is-no-mystery, the actor-playing-the-messiah of Mercer himself, set in the stony open-skied wasteland of existential openness. It seems to me that this is why Dick's styling of the androids as essentially children (the scene in which Pris indulges in the peculiarly infantile torture of cutting off a spider's legs has not lost its power to shock) works so well: children, generally speaking, inhabit worlds where authority is close, personal, intimate: parents or guardians never far away, God the Father living in their childish heads as versions of the same principle. Dick's androids are like the children in Lord of the Flies, only more so, because they do not have the conventional structures of social morality to lose. The novel as a whole is 170-pages that feel, in a good way, like 600.

The fourth novel in this compendium, Ubik, is probably the best of the lot, and a superbly controlled piece of work; or rather an expertly uncontrolled tumbling down the mountainside of SF and metaphysics. Joe Chip, a commercial precog, gets caught up in a tangled commercial espionage plot in a world where household appliances have minds of their own, people survive death in denuded cryonic "half-life" form, and the future—all our futures, death—haunts the present. He survives an attempt on his life, but finds a series of weird things happening in the world. In particular, entropic forces seem to be manifesting in malign and illogical ways: milks curdles unnaturally rapidly; Chip's futuristic car, for instance, changes into a 1939 LaSalle; and then into a 1929 Model-A Ford; an advanced radio becomes a clunky device with valves. Spraying a mystic aerosol called "Ubik" helps hold off this degeneration, but its effects are not permanent. The titular "Ubik," indeed, seems to be all commodities: chapter epigraphs wittily ring the ad-copy changes, from "the best way to ask for a beer is to sing out Ubik" via "wake up to a hearty, lip-smacking bowlful of nutritious nourishing Ubik" to, finally, the apotheosis of this ubiquitous principle of commercial exchange: "I am Ubik. Before the universe was, I am. I made the suns. I made the worlds. ... I am. I shall always be" (p. 797). In the light of this helter-skelter deconstruction of the props of modern capitalist existence, the snake-biting-its-take plot of whether Chip survived the bomb blast or whether it killed him trapping him in a half-life nightmare, though perfectly well handled, doesn't really seem somehow central.

Ubik not only feels like a longer novel than its 180-pages; it feels like several different novels in superposition. It is, for example, one of the most original spins on the time-travel premise of its era, as Dick's characters uncertainly seem (or perhaps, do) slide backwards through the twentieth-century. It is, as is most of Dick's fiction, an attempt at a metaphysical novel, in this case interrogating the place of Platonic idealism in a commodified world. It's also fast-paced futuristic spy-thriller, with characters batting between Earth and the Moon, getting into fights and explosions and life-or-death chases. Then again it works well as a comic novel, with some superbly funny satirical sequences. The scene where Chip cannot leave his own apartment until he pays the money his snooty door insists is its fee ("what I pay you," Chip argues, "is in the nature of a gratuity; I don't have to pay you." "I think otherwise," the door said. "Look in the purchase contract you signed when you bought this conapt," p. 629) is famous; but there are lots of similar, underplayed examples. Medical care on the moon is free, we're told, although "the burden of proof that he is genuinely ill rests on the shoulders of the alleged patient," (p. 665). I also liked Dick's sly snook-cocking at some of the conventions of pulp sf, for instance its habit of replacing contemporary profanity with nonsensical supposedly-futuristic ejaculations ("Who cares about the money? Snirt the money!" p. 623).

Re-reading these four novels was a stirring experience. It is a reminder of the fact that for Dick, though not for lesser writers, the point of art is not to represent reality, nor to improve it, but in some salutary sense to break it; to work towards some sort of explosive point of spilling-out, or generic transcendence. And the recommendation: the Library of America "Four Novels of the 1960s" is a simply splendid little volume, one of the best ways of accessing four of Dick's best novels. These black covers have swallowed four major novels, but the spine is slender and the meal only expands in the reader's mind. It's a pleasure to note that July 08 will see the publication of a follow-up volume, again edited by Lethem, containing Martian Time-Slip (1964), Dr Bloodmoney (1965), Now Wait For Last Year (1966), Flow My Tears, the Policeman Said (1974) and A Scanner Darkly (1977). Five of the longest short novels published.

Adam Roberts is a writer and critic of SF. He lives a little way west of London.