r Winter states that it would allow us to 'recreate a person physically, emotionally and spiritually', and estimates that the memory requirements would be about 10 terabytes (10e13 bytes), two orders of magnitude less than the petabyte (10e15 bytes) I suggest. And I wish I'd thought of Dr Winter's name for this device, which will certainly start some fierce debates in ecclesiastical circles: the 'Soul Catcher'... For its application to interstellar travel, see following note on Chapter 9. For an excellent history of the 'Beanstalk' concept (as well as many other even farther-out ideas such as anti-gravity and space-warps) see Robert L. Forward's "Indistinguishable From Magic" (Baen 1995). Chapter 7: Infinite Energy If the inconceivable energy of the Zero Point Field (sometimes referred to as 'quantum fluctuations' or 'vacuum energy') can ever be tapped, the impact upon our civilization will be incalculable. All present sources of power -- oil, coal, nuclear, hydro, solar -- would become obsolete, and so would many of our fears about environmental pollution. They would all be wrapped up in one big worry -- heat pollution. All energy eventually degrades to heat, and if everyone had a few million kilowatts to play with, this planet would soon be heading the way of Venus -- several hundred degrees in the shade. However, there is a bright side to the picture: there may be no other way of averting the next Ice Age, which otherwise is inevitable ('Civilization is an interval between Ice Ages' -- Will Durant: "The Story of Civilization", Fine Communications, US, 1993) Even as I write this, many competent engineers, in laboratories all over the world, claim to be tapping this new energy source. Some idea of its magnitude is contained in a famous remark by the physicist Richard Feynman, to the effect that the energy in a coffee-mug's volume (any such volume, anywhere!) is enough to boil all the oceans of the world. This, surely, is a thought to give one pause. By comparison, nuclear energy looks as feeble as a damp match. And how many supernovae, I wonder, really are industrial accidents? Chapter 9: Skyland One of the main problems of getting around in Star City would be caused by the sheer distances involved: if you wanted to visit a friend in the next Tower (and communications will never completely replace contact, despite all advances in Virtual Reality) it could be the equivalent of a trip to the Moon. Even with the fastest elevators this would involve days rather than hours, or else accelerations quite unacceptable to people who had adapted to low-gravity life. The concept of an 'inertialess drive' -- i.e. a propulsion system that acts on every atom of a body so that no strains are produced when it accelerates -- was probably invented by the master of the 'Space Opera', E.E. Smith, in the 1930s. It is not as improbable as it sounds -- because a gravitational field acts in precisely this manner. If you fall freely near the Earth (neglecting the effects of air resistance) you will increase speed by just under ten metres per second, every second. Yet you will feel weightless -- there will be no sense of acceleration, even though your velocity is increasing by one kilometre a second, every minute and a half! And this would still be true if you were falling in Jupiter's gravity (just over two-and-a-half times Earth's) or even the enormously more powerful field of a white dwarf or neutron star (millions or billions of times greater). You would feel nothing, even if you had approached the velocity of light from a standing start in a matter of minutes. However, if you were foolish enough to get within a few radii of the attracting object, its field would no longer be uniform over the whole length of your body, and tidal forces would soon tear you to pieces. For further details, see my deplorable but accurately-titled short story 'Neutron Tide' (in "The Wind from the Sun"). An 'inertialess drive', which would act exactly like a controllable gravity field, had never been discussed seriously outside the pages of science fiction until very recently. But in 1994 three American physicists did exactly this, developing some ideas of the great Russian physicist Andrei Sakharov. 'Inertia as a Zero-Point Field Lorentz Force' by B. Haisch, A. Rueda & H. F. Puthoff (Physics Review A, February 1994) may one day be regarded as a landmark paper, and for the purposes of fiction I have made it so. It addresses a problem so fundamental that it is normally taken for granted, with a that's-just-the-way-the-universe-is-made shrug of the shoulders. The question HR&P asked is: 'What gives an object mass (or inertia) so that it requires an effort to start it moving, and exactly the same effort to restore it to its original state?' Their provisional answer depends on the astonishing -- and outside the physicists' ivory towers -- little-known fact that so-called 'empty' space is actually a cauldron of seething energies -- the Zero-Point Field (see note above). HR&P suggest that both inertia and gravitation are electromagnetic phenomena, resulting from interaction with this field. There have been countless attempts, going all the way back to Faraday, to link gravity and magnetism, and although many experimenters have claimed success, none of their results has ever been verified. However, if HR&P's theory can be proved, it opens up the prospect -- however remote -- of anti-gravity, 'space drives' and the even more fantastic possibility of controlling inertia. This could lead to some interesting situations: if you gave someone the gentlest touch, they would promptly disappear at thousands of kilometres an hour, until they bounced off the other side of the room a fraction of a millisecond later. The good news is that traffic accidents would be virtually impossible; automobiles -- and passengers -- could collide harmlessly at any speed. (And you think that today's life-styles are already too hectic?) The 'weightlessness' which we now take for granted in space missions -- and which millions of tourists will be enjoying in the next century -- would have seemed like magic to our grandparents. But the abolition -- or merely the reduction -- of inertia is quite another matter, and may be completely impossible.* But it's a nice thought, for it could provide the equivalent of 'teleportation': you could travel anywhere (at least on Earth) almost instantaneously. Frankly, I don't know how 'Star City' could manage without it... -- -- -- -- -- -- * As every Trekker knows, the Starship Enterprise uses 'inertial dampers' to solve this particular problem. When asked how these work, the series' technical advisor gave the only possible answer: 'very well, thank you.' (See "The Physics of Star Trek" by Lawrence Krauss: HarperCollins, 1996.) -- -- -- -- -- -- One of the assumptions I have made in this novel is that Einstein is correct, and that no signal -- or object -- can exceed the speed of light. A number of highly mathematical papers have recently appeared suggesting that, as countless science-fiction writers have taken for granted, galactic hitch-hikers may not have to suffer this annoying disability. On the whole, I hope they are right -- but there seems one fundamental objection. If FTL is possible, where are all those hitchhikers -- or at least the well-heeled tourists? One answer is that no sensible ETs will ever build interstellar vehicles, for precisely the same reason that we have never developed coal-fuelled airships: there are much better ways of doing the job. The surprisingly small number of 'bits' required to define a human being, or to store all the information one could possibly acquire in a lifetime, is discussed in 'Machine Intelligence, the Cost of Interstellar Travel and Fermi's Paradox' by Louis K. Scheffer (Quarterly Journal of the Royal Astronomical Society, Vol. 35, No. 2, June 1994: pp. 157-75). This paper (surely the most mind-stretching that the staid QJRAS has published in its entire career!) estimates that the total mental state of a 100-year-old human with a perfect memory could be represented by 10 to the 15th bits (one petabit). Even today's optical fibres could transmit this amount of information in a matter of minutes. My suggestion that a Star Trek transporter would still be unavailable in 3001 may therefore appear ludicrously shortsighted a mere century from now* and the present lack of interstellar tourists is simply due to the fact that no receiving equipment has yet been set up on Earth. Perhaps it's already on its way by slow-boat... -- -- -- -- -- -- * However, for a diametrically opposing view, see the above-mentioned "Physics of Star Trek". -- -- -- -- -- -- Chapter 15: Falcon It gives me particular pleasure to pay this tribute to the crew of Apollo 15. On their return from the Moon they sent me the beautiful relief map of Falcon's landing site, which now has pride of place in my office. It shows the routes taken by the Lunar Rover during its three excursions, one of which skirted Earthlight Crater. The map bears the inscription: 'To Arthur Clarke from the crew of Apollo 15 with many thanks for your visions of space. Dave Scott, Al Worden, Jim Irwin.' In return, I have now dedicated "Earthlight" (which, written in 1953, was set in the territory the Rover was to drive over in 1971): 'To Dave Scott and Jim Irwin, the first men to enter this land, and to Al Worden, who watched over them from orbit.' After covering the Apollo 15 landing in the CBS studio with Walter Cronkite and Wally Schirra, I flew to Mission Control to watch the re-entry and splashdown. I was sitting beside Al Worden's little daughter when she was the first to notice that one of the capsule's three parachutes had failed to deploy. It was a tense moment, but luckily the remaining two were quite adequate for the job. Chapter 16: Asteroid 7794 See Chapter 18 of "2001: A Space Odyssey" for the description of the probe's impact. Precisely such an experiment is now being planned for the forthcoming Clementine 2 mission. I am a little embarrassed to see that in my first Space Odyssey the discovery of Asteroid 7794 was attributed to the Lunar Observatory -- in 1997! Well, I'll move it to 2017 -- in time for my 100th birthday. Just a few hours after writing the above, I was delighted to learn that Asteroid 4923 (1981 EO27), discovered by S. J. Bus at Siding Spring, Australia, on 2 March 1981, has been named Clarke, partly in recognition of Project Spaceguard (see "Rendezvous with Rama" and "The Hammer of God"). I was informed, with profound apologies, that owing to an unfortunate oversight Number 2001 was no longer available, having been allocated to somebody named A. Einstein. Excuses, excuses. But I was very pleased to learn that Asteroid 5020, discovered on the same day as 4923, has been named Asimov -- though saddened by the fact that my old friend could never know. Chapter 17: Ganymede As explained in the Valediction, and in the Author's Notes to "2010 Odyssey Two" and "2061 Odyssey Three", I had hoped that the ambitious Galileo Mission to Jupiter and its moons would by now have given us much more detailed knowledge -- as well as stunning close-ups -- of these strange worlds. Well, after many delays, Galileo reached its first objective -- Jupiter itself -- and is performing admirably. But, alas, there is a problem -- for some reason, the main antenna never unfolded. This means that images have to be sent back via a low-gain antenna, at an agonizingly slow rate. Although miracles of onboard computer reprogramming have been done to compensate for this, it will still require hours to receive information that should have been sent in minutes. So we must be patient -- and I was in the tantalizing position of exploring Ganymede in fiction just before Galileo started to do so in reality, on 27 June 1996. On 11 July 1996, just two days before finishing this book, I downloaded the first images from JPL; luckily nothing -- so far! --contradicts my descriptions. But if the current vistas of cratered ice-fields suddenly give way to palm trees and tropical beaches -- or, worse still, YANKEE GO HOME signs, I'll be in real trouble . I am particularly looking forward to close-ups of 'Ganymede City' (Chapter 17). This striking formation is exactly as I described it -- though I hesitated to do so for fear that my 'discovery' might be front-paged by the National Prevaricator. To my eyes it appears considerably more artificial than the notorious 'Mars Face' and its surroundings. And if its streets and avenues are ten kilometres wide -- so what? Perhaps the Medes were BIG... The city will be found on the NASA Voyager images 20637.02 and 20637.29, or more conveniently in Figure 23.8 of John H. Rogers's monumental "The Giant Planet Jupiter" (Cambridge University Press, 1995). Chapter 19: The Madness of Mankind For visual evidence supporting Khan's startling assertion that most of mankind has been at least partially insane, see Episode 22, 'Meeting Mary', in my television series Arthur C. Clarke's Mysterious Universe. And bear in mind that Christians represent only a very small subset of our species: far greater numbers of devotees than have ever worshipped the Virgin Mary have given equal reverence to such totally incompatible divinities as Rama, Kali, Siva, Thor, Wotan, Jupiter, Osiris, etc. etc.... The most striking -- and pitiful -- example of a brilliant man whose beliefs turned him into a raving lunatic is that of Conan Doyle. Despite endless exposures of his favourite psychics as frauds, his faith in them remained unshaken. And the creator of Sherlock Holmes even tried to convince the great magician Harry Houdini that he 'dematerialized' himself to perform his feats of escapology -- often based on tricks which, as Dr Watson was fond of saying, were 'absurdly simple'. (See the essay 'The Irrelevance of Conan Doyle' in Martin Gardner's "The Night is Large", St Martin's Press, US, 1996.) For details of the Inquisition, whose pious atrocities make Pol Pot look positively benign, see Carl Sagan's devastating attack on New Age Nitwittery, "The Demon-Haunted World: Science as a Candle in the Dark" (Headline, 1995). I wish it -- and Martin's book -- could be made required reading in every high school and college. At least the US Department of Immigration has taken action against one religion-inspired barbarity. Time Magazine ('Milestones', 24 June 1996) reports that asylum must now be granted to girls threatened with genital mutilation in their countries of origin. I had already written this chapter when I came across Anthony Storr's "Feet of Clay: A Study of Gurus" (HarperCollins, 1996), which is a virtual textbook on this depressing subject. It is hard to believe that one holy fraud, by the time the US Marshals belatedly arrested him, had accumulated ninety-three Rolls-Royces! Even worse -- eighty-three per cent of his thousands of American dupes had been to college, and thus qualify for my favourite definition of an intellectual: 'Someone who has been educated beyond his/her intelligence.' Chapter 26: Tsienville In the 1982 preface to "2010: Odyssey Two", I explained why I named the Chinese spaceship which landed on Europa after Dr Tsien Hsue-shen, one of the founders of the United States and Chinese rocket programmers. As Iris Chang states in her biography "Thread of the Silkworm" (Basic Books, 1995) 'his life is one of the supreme ironies of the Cold War'. Born in 1911, Tsien won a scholarship which brought him from China to the United States in 1935, where he became student and later colleague of the brilliant Hungarian aerodynamicist Theodore von Karman. Later, as first Goddard Professor at the California Institute of Technology, he helped establish the Guggenheim Aeronautical Laboratory -- the direct ancestor of Pasadena's famed Jet Propulsion Laboratory. With top secret clearance, he contributed greatly to American rocket research in the 1950s, but during the hysteria of the McCarthy era was arrested on trumped-up security charges when he attempted to pay a visit to his native China. After many hearings and a prolonged period of arrest, he was finally deported to his homeland -- with all his unrivalled knowledge and expertise. As many of his distinguished colleagues affirmed, it was one of the most stupid (as well as most disgraceful) things the United States ever did. After his expulsion, according to Thuang Fenggan, Deputy Director, China National Space Administration, Tsien 'started the rocket business from nothing... Without him, China would have suffered a twenty-year lag in technology.' And a corresponding delay, perhaps, in the deployment of the deadly 'Silkworm' anti-ship missile and the 'Long March' satellite launcher. Shortly after I had completed this novel, the International Academy of Astronautics honoured me with its highest distinction, the von Karman Award -- to be given in Beijing! This was an offer I couldn't refuse, especially when I learned that Dr Tsien is now a resident of that city. Unfortunately, when I arrived there I discovered that he was in hospital for observation, and his doctors would not permit visitors. I am therefore extremely grateful to his personal assistant, Major-General Wang Shouyun, for carrying suitably inscribed copies of 2010 and 2061 to Dr Tsien. In return the General presented me with the massive volume he has edited, "Collected Works of H. S. Tsien: 1938-1956" (1991, Science Press, 16, Donghuangcheggen North Street, Beijing 100707). It is a fascinating collection, beginning with numerous collaborations with von Karman on problems in aerodynamics, and ending with solo papers on rockets and satellites. The very last entry, 'Thermonuclear Power Plants' (Jet Propulsion, July 1956) was written while Dr Tsien was still a virtual prisoner of the FBI, and deals with a subject that is even more topical today -- though very little progress has been made towards 'a power station utilizing the deuterium fusion reaction'. Just before I left Beijing on 13 October 1996 I was happy to learn that, despite his current age (85) and disability, Dr Tsien is still pursuing his scientific studies. I sincerely hope that he enjoyed "2010" and "2061", and look forward to sending him this "Final Odyssey" as an additional tribute. Chapter 36: Chamber of Horrors As the result of a series of Senate Hearings on Computer Security in June 1996, on 15 July 1996 President Clinton signed Executive Order 13010 to deal with 'computer-based attacks on the information or communications components that control critical infrastructures ("cyber threats").' This will set up a task force to counter cyberterrorism, and will have representatives from the CIA, NSA, defense agencies, etc. Pico, here we come... Since writing the above paragraph, I have been intrigued to learn that the finale of the movie Independence Day, which I have not yet seen, also involves the use of computer viruses as Trojan horses! I am also informed that its opening is identical to that of Childhood's End (1953), and that it contains every known science-fiction clicheŽ since MeŽlie`s's Trip to the Moon (1903). I cannot decide whether to congratulate the script-writers on their one stroke of originality -- or to accuse them of the transtemporal crime of pre-cognitive plagiarism. In any event, I fear there's nothing I can do to stop John Q. Popcorn thinking that I have ripped off the ending of ID4. The following material has been taken -- usually with major editing -- from the earlier books in the series: From "2001 A Space Odyssey": Chapter 18 Through the Asteroids and Chapter 37 Experiment. From "2010: Odyssey Two": Chapter 11 Ice and Vacuum; Chapter 36 Fire in the Deep: Chapter 38 Foamscape. ACKNOWLEDGEMENTS My thanks to IBM for presenting me with the beautiful little Thinkpad 755CD on which this book was composed. For many years I have been embarrassed by the -- totally unfounded --rumour that the name HAL was derived by one-letter displacement from IBM. In an attempt to exorcise this computer-age myth, I even went to the trouble of getting Dr Chandra, HAL's inventor, to deny it in 2010 Odyssey Two. However, I was recently assured that, far from being annoyed by the association, Big Blue is now quite proud of it. So I will abandon any future attempts to put the record straight -- and send my congratulations to all those participating in HAL's 'birthday party' at (of course) the University of Illinois, Urbana, on 12 March 1997. Rueful gratitude to my Del Rey Books editor, Shelly Shapiro, for ten pages of niggles which, when dealt with, made a vast improvement to the final product. (Yes, I've been an editor myself, and do not suffer from the usual author's conviction that the members of this trade are frustrated butchers.) Finally, and most important of all: my deepest thanks to my old friend Cyril Gardiner, Chairman of the Galle Face Hotel, for the hospitality of his magnificent (and enormous) personal suite while I was writing this book: he gave me a Tranquillity Base in a time of troubles. I hasten to add that, even though it may not provide such extensive imaginary landscapes, the facilities of the Galle Face are far superior to those offered by the 'Grannymede', and never in my life have I worked in more comfortable surroundings. Or, for that matter, in more inspirational ones, for a large plaque at the entrance lists more than a hundred of the Heads of State and other distinguished visitors who have been entertained here. They include Yuri Gagarin, the crew of Apollo 12 -- the second mission to the Moon's surface -- and a fine collection of stage and movie stars: Gregory Peck, Alec Guinness, Noel Coward, Carrie Fisher of "Star Wars" fame... As well as Vivien Leigh and Laurence Olivier -- both of whom make brief appearances in "2061 Odyssey Three" (Chapter 37). I am honoured to see my name listed among them. It seems appropriate that a project begun in one famous hotel -- New York's Chelsea, that hotbed of genuine and imitation genius -- should be concluded in another, half a world away. But it's strange to hear the monsoon-lashed Indian Ocean roaring just a few yards outside my window, instead of the traffic along far-off and fondly remembered 23rd Street. IN MEM0RIAM: 18 SEPTEMBER 1996 It was with the deepest regret that I heard -- literally while editing this acknowledgements -- that Cyril Gardiner died a few hours ago. It is some consolation to know that he had already seen the above tribute and was delighted with it. VALEDICTION 'Never explain, never apologize' may be excellent advice for politicians, Hollywood moguls and business tycoons, but an author should treat his readers with more consideration. So, though I have no intention of apologizing for anything, perhaps the complicated genesis of the Odyssey Quartet requires a little explaining. It all began at Christmas 1948 -- yes, 1948! -- with a 4,000-word short story which I wrote for a contest sponsored by the British Broadcasting Corporation. 'The Sentinel' described the discovery of a small pyramid on the Moon, set there by some alien civilization to await the emergence of mankind as a planet-faring species. Until then, it was implied, we would be too primitive to be of any interest.* The BBC rejected my modest effort, and it was not published until almost three years later in the one-and-only (Spring 1951) issue of 10 Story Fantasy -- a magazine which, as the invaluable "Encyclopaedia of Science Fiction" wryly comments, is 'primarily remembered for its poor arithmetic (there were 13 stories)'. 'The Sentinel' remained in limbo for more than a decade, until Stanley Kubrick contacted me in the spring of 1964 and asked if I had any ideas for the 'proverbial' (i.e. still non-existent) 'good science-fiction movie'. During the course of our many brainstorming sessions, as recounted in "The Lost Worlds of 2001" (Sidgwick and Jackson, 1972) we decided that the patient watcher on the Moon might provide a good starting point for our story. Eventually it did much more than that, as somewhere during production the pyramid evolved into the now famous black monolith. -- -- -- -- -- -- * The search for alien artefacts in the Solar System should be a perfectly legitimate branch of science ('exo-archaeology'?). Unfortunately, it has been largely discredited by claims that such evidence has already been found -- and has been deliberately suppressed by NASA! It is incredible that anyone would believe such nonsense: far more likely that the space agency would deliberately fake ET artefacts -- to solve its budget problems! (Over to you, NASA Administrators...) -- -- -- -- -- -- To put the Odyssey series in perspective, it must be remembered that when Stanley and I started planning what we privately called 'How the Solar System was Won' the Space Age was barely seven years old, and no human had travelled more than a hundred kilometres from the home planet. Although President Kennedy had announced that the United States intended to go to the Moon 'in this decade', to most people that must still have seemed like a far-off dream. When filming started just west of London* on a freezing 29 December 1965, we did not even know what the lunar surface looked like at close quarters. There were still fears that the first word uttered by an emerging astronaut would be 'Help!' as he disappeared into a talcum-power-like layer of moondust. On the whole, we guessed fairly well: only the fact that our lunar landscapes are more jagged than the real ones -- smoothed by aeons of sand-blasting by meteoric dust -- reveals that 2001 was made in the pre-Apollo era. -- -- -- -- -- -- * At Shepperton, destroyed by the Martians in one of the most dramatic scenes in wells's masterpiece, The War of the Worlds. -- -- -- -- -- -- Today, of course, it seems ludicrous that we could have imagined giant space-stations, orbiting Hilton Hotels, and expeditions to Jupiter as early as 2001. It is now difficult to realize that back in the 1960s there were serious plans for permanent Moon bases and Mars landings -- by 1990! Indeed, in the CBS studio, immediately after the Apollo 11 launch, I heard the Vice-President of the United States proclaim exuberantly: 'Now we must go to Mars!' As it turned out, he was lucky not to go to prison. That scandal, plus Vietnam and Watergate, is one of the reasons why these optimistic scenarios never materialized. When the movie and book of "2001 A Space Odyssey" made their appearance in 1968, the possibility of a sequel had never crossed my mind. But in 1979 a mission to Jupiter really did take place, and we obtained our first close-ups of the giant planet and its astonishing family of moons. The Voyager space-probes* were, of course, unmanned, but the images they sent back made real -- and totally unexpected -- worlds from what had hitherto been merely points of light in the most powerful telescopes. The continually erupting sulphur volcanoes of Io, the multiply-impacted face of Callisto, the weirdly contoured landscape of Ganymede -- it was almost as if we had discovered a whole new Solar System. The temptation to explore it was irresistible; hence 2010 Odyssey Two, which also gave me the opportunity to find out what happened to David Bowman, after he had awakened in that enigmatic hotel room. -- -- -- -- -- -- * Which employed a 'slingshot' or 'gravity-assist' manoeuvre by flying close to Jupiter -- -- -- -- -- -- In 1981, when I started writing the new book, the Cold War was still in progress, and I felt I was going out on a limb -- as well as risking criticism -- by showing a joint US-Russian mission. I also underlined my hope of future co-operation by dedicating the novel to Nobelist Andrei Sakharov (then still in exile) and Cosmonaut Alexei Leonov -- who, when I told him in 'Star Village' that the ship would be named after him, exclaimed, with typical ebullience, 'Then it will be a good ship!' It still seems incredible to me that, when Peter Hyams made his excellent film version in 1983, he was able to use the actual close-ups of the Jovian moons obtained in the Voyager missions (some of them after helpful computer processing by the Jet Propulsion Laboratory, source of the originals). However, far better images were expected from the ambitious Galileo mission, due to carry out a detailed survey of the major satellites over a period of many months. Our knowledge of this new territory, previously obtained only from a brief flyby, would be enormously expanded -- and I would have no excuse for not writing "Odyssey Three". Alas -- something tragic on the way to Jupiter. It had been planned to launch Galileo from the Space Shuttle in 1986 -- but the Challenger disaster ruled out that option, and it soon became clear -- precisely as was done by Discovery in the book version of 2001 -- that we would get no new information from Io and Europa, Ganymede and Callisto, for at least another decade. I decided not to wait, and the (1985) return of Halley's Comet to the inner Solar System gave me an irresistible theme. Its next appearance in 2061 would be good timing for a third Odyssey, though as I was not certain when I could deliver it I asked my publisher for a rather modest advance. It is with much sadness that I quote the dedication of "2061 Odyssey Three": TO THE MEMORY OF JUDY-LYNN DEL REY, EDITOR EXTRAORDINARY, who bought this book for one dollar -- but never knew if she got her money's worth. Obviously there is no way in which a series of four science-fiction novels, written over a period of more than thirty years of the most breathtaking developments in technology (especially in space exploration) and politics, could be mutually consistent. As I wrote in the introduction to 2061: 'Just as 2010 was not a direct sequel to 2001, so this book is a not a linear sequel to 2010. They must all be considered as variations on the same theme, involving many of the same characters and situations, but not necessarily happening in the same universe.' If you want a good analogy from another medium, listen to what Rachmaninoff and Andrew Lloyd Webber did to the same handful of notes by Paganini. So this "Final Odyssey" has discarded many of the elements of its precursors, but developed others -- and I hope more important ones -- in much greater detail. And if any readers of the earlier books feel disorientated by such transmutations, I hope I can dissuade them from sending me angry letters of denunciation by adapting one of the more endearing remarks of a certain US President: 'It's fiction, stupid!' And it's all my own fiction, in case you hadn't noticed. Though I have much enjoyed my collaborations with Gentry Lee,* Michael Kube-McDowell and the late Mike McQuay -- and won't hesitate again to call on the best hired guns in the business if I have future projects that are too big to handle myself -- this particular Odyssey had to be a solo job. -- -- -- -- -- -- * By an unlikely coincidence, Gentry was Chief Engineer on the Galileo and Viking projects. (See Introduction to Rama II). It wasn't his fault that the Galileo antenna didn't unfurl... -- -- -- -- -- -- So every word is mine: well, almost every word, I must confess that I found Professor Thirugnanasampanthamoorthy (Chapter 35) in the Colombo Telephone Directory; I hope the present owner of that name will not object to the loan. There are also a few borrowings from the great Oxford English Dictionary. And what do you know -- to my delighted surprise, I find it uses no fewer than 66 quotations from my own books to illustrate the meaning and use of words! Dear OED, if you find any useful examples in these pages, please be my guest -- again. I apologize for the number of modest coughs (about ten, at last count) in this Afterword; but the matters to which they drew attention seemed too relevant to be omitted. Finally, I would like to assure my many Buddhist, Christian, Hindu, Jewish and Muslim friends that I am sincerely happy that the religion which Chance has given you has contributed to your peace of mind (and often, as Western medical science now reluctantly admits, to your physical well-being). Perhaps it is better to be un-sane and happy, than sane and un-happy. But it is best of all to be sane and happy. Whether our descendants can achieve that goal will be the greatest challenge of the future. Indeed, it may well decide whether we have any future. Arthur C. Clarke Colombo, Sri Lanka 19 September 1996