Much was made in initial reviews of And Another Thing . . ., the new Hitchhiker's Guide to the Galaxy novel, of how Eoin Colfer, known for his comically inventive "Artemis Fowl" young adult fantasy sequence, has apparently "channelled" Douglas Adams. Mark Lawson in The Guardian wrote that "Eoin Colfer has achieved the best post-mortem impersonation I have ever read. If Adams's family had chosen to tout this manuscript as an original novel discovered in a cupboard, their subterfuge would have been hard to rumble." Euan Ferguson in The Observer called it "a triumph. Colfer has pulled off the near-impossible. It's faithful to Adams's humour and, more important, it's also got his rhythm, the cadences and the footfalls that made his style so often (badly) imitated."

Perhaps. And certainly the "sequel by other hands" is established enough as a literary tradition for complaints about it to be dismissed as whines from the purists. If an audience wants more, who is a literary estate to get in their way? Plenty of writers have taken a series or a set of characters past their sell-by date, and while there have been some thoroughly awful examples, it doesn't have to be the case that such a venture is always a failure: some of the various James Bond reincarnations have been decent enough reads.

However, the problem here is which Douglas Adams is being channeled. When the new edition of So Long, and Thanks For All The Fish comes with an introduction (by Neil Gaiman) which tells us that whatever Adams was, he was not a novelist, we need to ask this question. As Gaiman points out, in many ways Adams was brilliantly inventive, and in particular "an astonishing comic writer." The Hitchhiker's Guide to the Galaxy was, as a comic radio SF serial, unsurpassable. There are numerous traps to be laid in the way of funny SF on radio, and Adams fell into none of them. But his genius was for lines which are funny precisely because they sound funny and reinforce rather than undercut the bizarre situations and images. When Arthur and Ford first meet Zaphod on board the Heart of Gold, for instance (Ford: "Zaphod . . . the extra arm suits you," followed by Arthur's declaration that he and Zaphod have met: "he only had the two arms and the one head and he called himself Phil . . ."), what makes the scene work is, first, that the lines are delivered with Ford's exaggerated cool and Arthur's petulant exasperation, and second, that we're freed from the defects of both print and television. The novel gives us our reaction in advance ("Ford was not going to be outcooled"), while in the TV and film adaptations we can see that Zaphod has more limbs and heads than the usual and so the brilliance of Arthur's trumping the extra arm with one (or more) heads is lost. (In a footnote in The Original Radio Scripts, Adams describes this as a "little extra throwaway joke," but sometimes the throwaway jokes are the best.) As Gaiman warns us, So Long . . . was Adams’s first attempt to write a novel from scratch, and his attempts to make it appeal to the fans, move away from the surreal farce of the radio scripts, and possess the seriousness of real novels were, though Gaimain is too charitable to tell us, disastrous. It is a novel written because the audience wanted it, not because it needed to be written, and the introduction of a love story and the cringing uncertainty of the question “Does [Arthur] not, to put it in a nutshell, fuck?” undermines everything that has been written so far. Its tone is sheer embarrassment, and Adams’s later writing out of Arthur’s love Fenchurch is downright cruel: Arthur may be a one-dimensional comic character but he’s our one-dimensional comic character and he deserves better than that.

(If that sounds a harsh judgment on Adam’s ability as a novelist, let it be said that the two Dirk Gently books, which did not begin as radio dramatizations, work much better.)

Colfer begins And Another Thing . . . following, we remember, the end of Mostly Harmless in which “it was now all, finally, over” (although the 2005 radio adaptation by Dirk Maggs gives us an alternative ending). It takes us some few pages for Colfer to leap into the continuum of this particular book, and the gathering of Arthur, Ford, Trillian, and Random in one place, but he does so ingeniously, via an explanation by the Hitchhiker’s Guide to the Galaxy Mark 2 to a Ford who has spent the past twenty years in a virtual reality pleasure palace. Meanwhile, Trillian Astra, ace interplanetary news reporter, and her daughter, Galactic President Random Dent, are transported to a beach on which the old man vegetating among confused memories turns out to be Arthur. Of course, you can explain anything through the medium of "parallel universes," which was the reason why the previous two novels existed in the first place, and it is tempting to dismiss this trick as the old hack "with one bound, Jack was free" or ". . . and then I woke up and it had all been a dream." But one of the joys of Hitchhiker's has been the way every single medium's "version" of the story has been different, and although this doesn't, I think, invalidate my feeling that the whole thing works best as an audio dramatisation, it does make perfect sense in terms of starting off a new episode.

And so, following some waving of hands about how the Guide Mark 2 set up the virtuality in order to allow Random to live her life as she would have wished, we are back at Club Beta where the Vogons are once more about to destroy the Earth, and our intrepid (if quarrelsome) heroes are once more picked up in the nick of time by Zaphod in the Heart of Gold. Ford, though, manages to undermine the confidence of Zaphod's left brain (now interfacing with the Improbability Drive) in numerical calculation and freezes the ship. Almost immediately, Wowbagger the Infinitely Prolonged bangs on the door, insults Zaphod, and is persuaded to rescue everyone on the promise of being introduced to a god who would bring to an end his now tedious existence.

The Earth is once more destroyed, and Arthur and co. are on their travels.

The rest of the novel involves, among other things: a romance between Wowbagger and Trillian; the return of Prostetnic Vogon Jeltz and the introduction of his son (who is something of a rebel, at least in Vogon terms); a computer simulation of Arthur's lost love Fenchurch; an official of the planet Nano, Hillman Hunter, who is interviewing for presiding deities (the interview with Cthullhu is a delight); and of course Thor. Hillman and the Nanoites are, it turns out, the last remaining Earth people, who the Vogons are planning to destroy to fulfil their contractual obligations. Zaphod, inevitably, is involved in all of this, and in particular in Thor's attempt to make a comeback, which involves another scene in Asgard during which Colfer's ability to devise and follow through with ingenious subplots is once more highlighted.

My feeling about the book has changed several times in the process of reading and re-reading. Most notably, my sense of the way the third chapter (described above) handled the few seconds between the appearance of the Heart of Gold as the Grebulon death-rays are about to be unleashed and the rescue by Wowbagger's dark-space traversing Tanngrisnir was altered between the time I heard it read on BBC Radio 4's "Book at Bedtime" serialisation and actually reading the text for myself. On hearing it, I was irritated beyond measure by the fact that during the fifteen minutes of narration, nothing at all actually happened. On reading it, it was obvious to me that that was precisely the point, and it was thoroughly obtuse of me not to have noticed the joke. We can argue about whether it was an effective joke, but whether or not it was, the idea of having our characters squabble at the cusp of a rescue was at least an ingenious attempt by Colfer to bring everyone together and at the same time send up the process of the coincidental rescue, and establishes the nod to Pythonesque humour which any adaptation of Adams should possess.

On the other hand, while what Colfer has added to what we know of the appalling Vogons is almost entirely good fun which we could do with even more of, the more obvious echoes of Adams's style—the "Guide Notes" and "Related Reading" which replace the extracts from the "Book" in earlier incarnations, and the aside jokes such as "Zaphod whistled the first bar of ‘Blinko in the Baybox,’ an old Betelgeusian epic shanty concerning a pickled mollusc and his time spent in captivity"—still tend to come across as exactly the sort of things you do when you imitate Adams. But on the other hand (if we can borrow Zaphod's extra arm for a moment), Colfer has certainly woven what appears at first sight to be a series of sketches into a multi-layered plot, something that Adams's own novels often fail to do. Although the overblown Oirishness of Hillman Hunter is something that only an Irish writer could get away with, the way his subplot suddenly meshes with Zaphod's manipulation of Thor's is accomplished. The problem here is not that the whole is not the sum of the parts; it's that many of the parts are hardly necessary, whereas in Adams the parts were the point and the lack of plot, stability, and even sense about the unexpected digressions was precisely what we loved about them.

Another problem is Arthur, or what Arthur represents about the nature of the series. Over the course of the novels, Arthur has changed from being a gloriously comic stereotype EveryEnglishman, a universal fall guy, to someone who hurts and bleeds, a Candide, Voltaire's universal victim to whom all sorts of nasty things happen. That sort of thing has been a staple of comedy for all time. One of the reasons Laurel and Hardy are so effective is because when one of them swings round with a ladder or a plank and hits the other one in the face, we are aware that it hurts and our joy at slapstick is immediately undercut by our shame at laughing at an injury. But when an annoyed Arthur asks, late on in this novel, "Is this the time for jokes, Ford? Is it really?" the question makes no sense, because in a universe ruled by the kind of illogic that Adams's is it should never be not the time for jokes, or at least surreal situation-gags. This Arthur, an Arthur who feels, who has been in love and lost his love and who is anguished instead of exasperated at the destruction of his world, is not the same Arthur who asks how on Earth he is going to operate his digital watch now that his left arm has come off, or who could never get the hang of Thursdays. This isn't whimsical English melancholy any more. Perhaps one reason for the absence of the series’ second most effective character, Marvin, is because the terrible pain in all the diodes down his left side would turn out to be real pain. There is only so far you can go with jokes about serious depression. Random's teenage angst is almost a substitute, but Random never was an essential character and exists only to give Arthur the annoyances of parenthood.

Which is not, of course, to say that a Hitchhiker's Guide to the Galaxy which obtains its satiric effect by loading every possible craziness upon the shoulders of an innocent we empathize with should not exist, nor even that, along with depression, Pythonesque slapstick is something which can only go so far. Once Adams was no longer writing for radio, he had to change the tone. He was right to do so. And this is not 1978 any longer. There is no way a novelist like Eoin Colfer could have channelled the anarchy of those radio scripts, which were fuelled by the spirit of going into unexplored territory. Once we encounter something utterly unlike anything we have encountered before, we ask for the same. And Another Thing . . . (its title surely gives it away) tries to be the same, only different, and somewhat to my surprise it often succeeds. It is, as Mark Lawson notes, a successful pastiche to the extent that it even reads like a Douglas Adams outtake—but an outtake from the novels. And Another Thing . . . would have been a lot worse if So Long, and Thanks for All the Fish and Mostly Harmless had not been written, which is a very odd, even uncharitable thing to find yourself saying about a novel that delivers what was asked of it.

Andy Sawyer is librarian of the Science Fiction Foundation Collection at the University of Liverpool Library, Course Director of the MA in Science Fiction Studies offered by the School of English, and a widely published critic. He is Reviews Editor of Foundation: The International Review of Science Fiction. He recently co-edited (with David Ketterer) Plan for Chaos, a previously unpublished novel by John Wyndham. He is the 2008 recipient of the Clareson Award for services to science fiction.