'Boggling.'

'– nonsense, which surely any rational person would dismiss out of hand.'

'Examples, please.'

'Well, your really trivial loss started me doing some research, and I was appalled by what I found. Did you know that every year in some countries thousands of little girls were hideously mutilated to preserve their virginity? Many of them died – but the authorities turned a blind eye.'

'I agree that was terrible – but what could my government do about it?'

'A great deal – if it wished. But that would have offended the people who supplied it with oil and bought its weapons, like the landmines that killed and maimed civilians by the thousand.'

'You don't understand, Indra. Often we had no choice: we couldn't reform the whole world. And didn't somebody once say "Politics is the art of the possible"?'

'Quite true – which is why only second-rate minds go into it. Genius likes to challenge the impossible.'

'Well, I'm glad you have a good supply of genius, so you can put things right.'

'Do I detect a hint of sarcasm? Thanks to our computers, we can run political experiments in cyberspace before trying them out in practice. Lenin was unlucky; he was born a hundred years too soon. Russian communism might have worked – at least for a while – if it had had microchips. And had managed to avoid Stalin.'

Poole was constantly amazed by Indra's knowledge of his age – as well as by her ignorance of so much that he took for granted. In a way, he had the reverse problem. Even if he lived the hundred years that had been confidently promised him, he could never learn enough to feel at home. In any conversation, there would always be references he did not understand, and jokes that would go over his head. Worse still, he would always feel on the verge of some "faux pas" – about to create some social disaster that would embarrass even the best of his new friends...

Such as the occasion when he was lunching, fortunately in his own quarters, with Indra and Professor Anderson. The meals that emerged from the autochef were always perfectly acceptable, having been designed to match his physiological requirements. But they were certainly nothing to get excited about, and would have been the despair of a twenty-first-century gourmet.

Then, one day, an unusually tasty dish appeared, which brought back vivid memories of the deer-hunts and barbecues of his youth. However, there was something unfamiliar about both flavour and texture, so Poole asked the obvious question.

Anderson merely smiled, but for a few seconds Indra looked as if she was about to be sick. Then she recovered and said: 'You tell him – after we've finished eating.'

Now what have I done wrong? Poole asked himself. Half an hour later, with Indra rather pointedly absorbed in a video display at the other end of the room, his knowledge of the Third Millennium made another major advance.

'Corpse-food was on the way out even in your time,' Anderson explained. 'Raising animals to – ugh – eat them became economically impossible. I don't know how many acres of land it took to feed one cow, but at least ten humans could survive on the plants it produced. And probably a hundred, with hydroponic techniques.

'But what finished the whole horrible business was not economics – but disease. It started first with cattle, then spread to other food animals – a kind of virus, I believe, that affected the brain, and caused a particularly nasty death. Although a cure was eventually found, it was too late to turn back the clock – and anyway, synthetic foods were now far cheaper, and you could get them in any flavour you liked.'

Remembering weeks of satisfying but unexciting meals, Poole had strong reservations about this. For why, he wondered, did he still have wistful dreams of spare-ribs and cordon bleu steaks?

Other dreams were far more disturbing, and he was afraid that before long he would have to ask Anderson for medical assistance. Despite everything that was being done to make him feel at home, the strangeness and sheer complexity of this new world were beginning to overwhelm him. During sleep, as if in an unconscious effort to escape, he often reverted to his earlier life: but when he awoke, that only made matters worse.

He had travelled across to America Tower and looked down, in reality and not in simulation, on the landscape of his youth – and it had not been a good idea. With optical aid, when the atmosphere was clear, he'd got so close that he could see individual human beings as they went about their affairs, sometimes along streets that he remembered...

And always, at the back of his mind, was the knowledge that down there had once lived everyone he had ever loved, Mother, Father (before he had gone off with that Other Woman), dear Uncle George and Aunt Lil, brother Martin – and, not least, a succession of dogs, beginning with the warm puppies of his earliest childhood and culminating in Rikki.

Above all, there was the memory – and mystery – of Helena...

It had begun as a casual affair, in the early days of his astrotraining, but had become more and more serious as the years went by. Just before he had left for Jupiter, they had planned to make it permanent when he returned.

And if he did not, Helena wished to have his child. He still recalled the blend of solemnity and hilarity with which they had made the necessary arrangements...

Now, a thousand years later, despite all his efforts, he had been unable to find if Helena had kept her promise. Just as there were now gaps in his own memory, so there were also in the collective records of Mankind. The worst was that created by the devastating electromagnetic pulse from the 2304 asteroid impact, which had wiped out several per cent of the world's information banks, despite all backups and safety systems. Poole could not help wondering if, among all the exabytes that were irretrievably lost, were the records of his own children: even now, his descendants of the thirtieth generation might be walking the Earth; but he would never know.

It helped a little to have discovered that – unlike Aurora -some ladies of this era did not consider him to be damaged goods. On the contrary: they often found his alteration quite exciting, but this slightly bizarre reaction made it impossible for Poole to establish any close relationship. Nor was he anxious to do so; all that he really needed was the occasional healthy, mindless exercise.

Mindless – that was the trouble. He no longer had arty purpose in life. And the weight of too many memories was upon him; echoing the title of a famous book he had read in his youth, he often said to himself, 'I am a Stranger in a Strange Time.'

There were even occasions when he looked down at the beautiful planet on which – if he obeyed doctor's orders – he could never walk again, and wondered what it would be like to make a second acquaintance with the vacuum of space. Though it was not easy to get through the airlocks without triggering some alarm, it had been done: every few years, some determined suicide made a brief meteoric display in the Earth's atmosphere.

Perhaps it was just as well that deliverance was on its way, from a completely unexpected direction.

* * *

'Nice to meet you, Commander Poole – for the second time.'

'I'm sorry – don't recall – but then I see so many people.'

'No need to apologize. First time was out round Neptune.'

'Captain Chandler – delighted to see you! Can I get something from the autochef?'

'Anything with over twenty per cent alcohol will be fine.'

'And what are you doing back on Earth? They told me you never come inside Mars orbit.'

'Almost true – though I was born here, I think it's a dirty, smelly place – too many people – creeping up to a billion again!'

'More than ten billion in my time. By the way, did you get my "Thank you" message?'