The news last fall that Syfy is developing 3001: The Final Odyssey into a miniseries reminded the world that there are multiple sequels to 2001: A Space Odyssey, written by the author who developed the original story with director Stanley Kubrick. Much of the series is about moons, and Clarke’s sequels are not unlike moons in the 2001 system: they’ll never compete with the main event, but they’re forever tied to it.

The relationship between page and screen with respect to 2001 — widely regarded as not just one of the greatest science fiction films, but one of the greatest films full stop, of all time — has always been complicated. The collaboration between Kubrick and Clarke in creating 2001 was unique: the film was neither adapted from a pre-existing novel, nor “novelized” after the screenplay had been written. The film and novel were created simultaneously, though not always in accord with each other.

The road that led to 2001 began in 1964, when Kubrick (then 35) wrote to Clarke (then 46) suggesting that the two might collaborate to make the “proverbial good science-fiction movie.” Kubrick had admired Clarke’s writing, and the two initially discussed the idea of combining several of Clarke’s existing short stories to be adapted by Kubrick. Eventually, the two decided to jointly create a new novel/feature-length story inspired by Clarke’s 1948 story “The Sentinel.”

Though it was just a few pages long, “The Sentinel” contained the core premise of 2001: the discovery of an artifact placed on the Moon millennia ago by an extraterrestrial intelligence that was waiting for humanity to achieve spaceflight and discover the artifact, which would then function as a beacon and signal the arrival of intelligent life in our solar system. In “The Sentinel,” the artifact was a “roughly pyramidal structure” that glittered “like a gigantic, many-faceted jewel.” Clarke and Kubrick turned that into a crystalline rectangle, which proved impossible to film convincingly (Kubrick commissioned, then discarded, a three-ton block of lucite) and thus became the iconic ebon monolith.

When filming began in December 1965, Clarke and Kubrick were still trying to figure out exactly how the story would unfold. Clarke’s diary, portions of which were published in The Lost Worlds of 2001, details a constant back-and-forth between the two as Kubrick filmed in England and Clarke wrote — sometimes in Ceylon, sometimes at the Chelsea Hotel.

Clarke, who had learned the value of speed and decisiveness as a writer for the pulps, had completed a full draft of the novel as early as the end of 1964, but then continued to revise his manuscript as the movie was made. In summer 1966, a revised version of the novel was ready to go to the printers so as to be published in advance of the film release, but Kubrick (to Clarke’s chagrin) refused to sign the contract, and the final version of the novel wasn’t published until summer 1968, several months after the film’s January release.

One reason for the delay was to help ensure that the novel would match up with the film, which had evolved on a daily basis during filming while Kubrick dealt with technical obstacles and experimented with various scenarios to see what would work on screen. Despite that precaution, Clarke’s novel was still quite different — in some ways, startlingly different — than Kubrick’s film.

There are a few plot divergences between the film and novel, but they’re relatively minor: in the novel, Discovery goes to Saturn rather than Jupiter; there’s some variation in the way the confrontation between Bowman and HAL unfolds. What’s most strikingly different between the two is style. While Kubrick’s film is audaciously silent — notably in the famously wordless opening and closing segments — Clarke’s novel is intensely wordy.

Of course, anyone would be hard put to translate Kubrick’s cosmic imagery into words — but here, it’s important to remember that Clarke wasn’t adapting the completed film, he was articulating the plot he and Kubrick had been discussing for years. Clarke’s novel makes explicit what was only implied in the the film: that the Monoliths were dispatched by an alien intelligence, and that the first Monolith inspires primitive humans to start using tools while the last Monolith serves as a Star Gate through which Bowman directly encounters the aliens themselves.

In the novel, we learn the name of the chief ape — Moon-Watcher — and get a detailed account of how, precisely, the Monolith (still described as “completely transparent”) works its mojo. The Monolith fills with colors and patterns, then possesses the apes’ bodies as if they were “controlled by invisible strings” to teach the apes fine motor skills. It’s infinitely less satisfying than the movie sequence in which it slowly dawns on the ape that a bone can be used as a tool, and after a horrifying display of violence the bone becomes an orbiting nuclear weapon in the most famous jump cut in film history.

Similarly, Bowman’s ultimate journey through the Star Gate is detailed at length, with pages and pages of travelogue delivered in a chatty tone that’s worlds away from the stunned, frightened mood of the film’s final sequence. The best passage in this section is the surreal revelation that the books in Bowman’s artificial hotel suite are all completely blank and that there’s a kitchen stocked with boxes and cans containing “a slightly moist blue substance, about the weight and texture of bread pudding.”

The 1972 book The Lost Worlds of 2001 contains long sections of earlier drafts, revealing that the story — or at least Clarke’s version of it — had initially been even more concrete. In one version of what became 2001, we even meet an alien: a tall humanoid named Clindar who personally intervenes in the apes’ development and, millions of years later, greets the Discovery astronauts when they pass through the Star Gate and land on his lawn. (Yes, there’s literally a lawn.)

This may seem laughable in comparison to the profound awe of Kubrick’s finished film, but it’s no coincidence that Kubrick chose Clarke as a collaborator. While 2001 was initially greeted as a crazy trip, much of its enduring appeal derives from the fact that there is indeed an overarching plot tying the film’s three sections together. While Kubrick prefers an artful ambiguity to Clarke’s discursive literalism, it’s Clarke’s story that gives the film its spine.

That spine would be extended in 1982, by Clarke alone. Inspired by the Voyager images of Jupiter’s moons, Clarke decided to revisit the story that had made him world-famous. Deferring to the film’s version of events—in which the astronauts’ destination was Jupiter — Clarke continued the narrative in 2010: Odyssey Two.

Considered purely as a book, 2010 is the most satisfying of Clarke’s four novels in the series. It benefits from a close chronological tie to 2001, from a plot that’s more conventional (and, in conventional ways, more satisfying) than any of the other three books’, and by far the most fully-developed group of characters to populate any installment of the series.

The novel, assuming the Cold War would still be ongoing in 2010, describes a joint U.S.-Soviet mission to Jupiter, where Discovery has been parked in orbit since being abandoned by Bowman under mysterious circumstances nine years earlier. Heading the American team is Heywood Floyd, the administrator who had an extended role in 2001 (he’s the guy who’s seen flying up to the Moon on a shuttle, then briefing the staff at Clavius Base). The mission succeeds in docking with Discovery and reactivating HAL in what Microsoft would call “safe mode,” only to be warned — seemingly by the Star Child himself, Dave Bowman — that they are in danger.

By the early 80s, Kubrick’s 2001 had become an acclaimed classic, and when Clarke published the screen-ready 2010, there was little delay in turning it into a movie. Kubrick declined the invitation to direct the film himself, but didn’t stand in the way of genre specialist Peter Hyams, who took the helm with Roy Scheider in the role of Floyd (original actor William Sylvester was approached, but demurred) and adapted Clarke’s novel into 2010: The Year We Make Contact, released two years after the book.

The critical consensus in 1984 still seems about right three decades later: 2010 is not, and never could have been, a masterpiece on the order of 2001, but for what it is, it’s actually pretty good. Hyams rose to the occasion and produced several compelling sequences, incorporating — to Clarke’s delight — actual imagery returned by the Voyager missions. Keir Dullea returned as Bowman, and Douglas Rain reprised his role as the voice of HAL; the power of the original film is such that their appearances in 2010 pack an uncanny punch.

The 2010 book and film also helped to canonize a line that appeared in the 2001 novel but isn’t heard in the movie: Bowman’s last transmission, “My God — it’s full of stars!” 2010 ends with a bang, and resolves on a satisfying note that Hyams elegantly translated on film.

The franchise could have ended there — but Clarke was charged up. Though the film was inevitably regarded by trufans as a disappointment, the novel 2010 had won widespread acclaim as one of the best books of the author’s long career, and Clarke waited only five more years before penning another sequel.

2061: Odyssey Three again features Heywood Floyd, still hale and horny at age 103 thanks to the wonders of mid-21st century medicine and his permanent residence in low-gravity Earth orbit. He jumps a celebrity cruise to rendezvous with Halley’s Comet, but after landing on the comet his ship is rerouted to run a rescue mission to the Jovian moon of Europa, where a space crew including his grandson has landed in violation of the Monoliths’ express orders (issued at the end of 2010).

Clarke’s second sequel is the most mundane of his three 2001 follow-ups: the Monoliths exert virtually no influence on the story’s events. The scientifically-informed description of imagined environments, a favorite concern of the author’s since the first drafts of 2001, decisively takes center stage: the first half of 2061 is largely occupied by a description of what it might be like to land on a comet, and the second half examines the world of Europa as it has come to be in Clarke’s imagined future history.

Though we’re set up for suspense involving the marooned spaceship, the situation is resolved with surprisingly little drama; Clarke seems to have lost interest in developing a conventionally compelling plot, and neither the solar system nor any of the people in it are transformed over the course of the story to the extent they were in 2001 and 2010. The story is certainly a far less obvious candidate for screen adaptation than 2010 was, which may in part be why no such adaptation was ever made.

Now we’re about to have an adaptation of 3001, though in some ways Clarke’s last novel in the series seems even less camera-ready than 2061. The book, published ten years after its predecessor, begins with the exhumation of Frank Poole — Bowman’s Discovery co-pilot, who died and was consigned to the cosmos in 2001. Clarke posits that turn-of-the-millennium technology is able to revive Poole, who wakes with a start and turns out to have a personality that’s completely indistinguishable from the Heywood Floyd who served as our guide through 2010 and 2061.

This time, Clarke runs well over halfway through the book before there’s any more than a gentle whisper of a plot. Poole gets a leisurely introduction to 31st-century life, with dizzying towers connecting Earth’s surface to an orbiting world. He has a genial reunion, via mind-melding “braincap,” with his former shipmates; some decades later, very suddenly, word comes that the Monoliths may pose an imminent threat to humanity. The book’s denouement feels hasty and silly, as if rushed along so that Clarke could get to the part of the book he really cares about: the appendix where he discusses the scientific bases of all the technological developments he posits.

It seems highly unlikely that the Syfy miniseries will hew particularly closely to any of this. Likely the world’s general configuration will be preserved, and a revived Poole as central character makes sense. The general idea that the Monoliths may become hostile seems compelling, but beyond that, it’s hard to imagine importing much more of Clarke’s story.

That may seem sad to acknowledge, but from the outset, Clarke was never a filmmaker; nor, even, is he much of a storyteller. The device of science fiction, for Clarke, was a convenient and rewarding way to set his imagination free to extrapolate from known scientific principles. With 2010 Clarke demonstrated the ability to craft a satisfying plot, but though that ability was decreasingly in evidence afterwards, it may not be that he lost it. Rather, he seems to have, in his later years, stopped wanting it. Clarke knew where his interests were, and his most devoted readers were happy to follow him there.

Clarke writes in a postscript to 3001 that though he was by that point frequently collaborating with other authors, he decided to write the final book in the 2001 series entirely on his own because “this particular Odyssey had to be a solo job.” It’s easy to understand why Clarke felt such a strong personal connection to the series that transformed his life, but the irony of Clarke’s decision to go it alone for the last three books is that it’s precisely the collaboration with Kubrick that made 2001 great. The further Clarke’s series continues past that initial spark, the less compelling it becomes.

In that same postscript, Clarke makes clear what attentive readers will already have gathered: that he intended the four books to be variations on a theme rather than consistent chapters in a cohesive narrative. (Clarke’s contemporary Isaac Asimov had exactly the opposite impulse and spent his own final years writing novels that united his three best-known series into a single, epic future history that ultimately spanned 14 novels and dozens of short stories.)

That perspective makes the idea of deviating from Clarke’s text, in a film adaptation, less an apostasy than a necessity. Clarke himself understood that; though he was closely involved with the making of both the 2001 and 2010 movies, he acknowledged their directors’ need to have creative freedom, and he consistently praised both films to the end of his days. Clarke knew that his own world was on the page, and that’s where it will remain.

– Jay Gabler