Next came the skull-cap itself, a metal helmet that fitted snugly almost down to the ears, and triggered a nostalgic thought – wish my Jewish friends could see me now! After a few minutes, it was so comfortable that he was unaware of its presence.

Now he was ready for the installation – a process which, he realized with something akin to awe, had been the Rite of Passage for almost all the human race for more than half a millennium.

'There's no need to close your eyes,' said the technician, who had been introduced by the pretentious title of 'Brain Engineer' – almost always shortened to 'Brainman' in popular usage. 'When Setup begins, all your inputs will be taken over. Even if your eyes are open, you won't see anything.'

I wonder if everyone feels as nervous as this, Poole asked himself. Is this the last moment I'll be in control of my own mind? Still, I've learned to trust the technology of this age; up to now, it hasn't let me down. Of course, as the old saying goes, there's always a first time...

As he had been promised, he had felt nothing except a gentle tickling as the myriad of nanowires wormed their way through his scalp. All his senses were still perfectly normal; when he scanned his familiar room, everything was exactly where it should be.

The Brainman – wearing his own skull-cap, wired, like Poole's, to a piece of equipment that could easily have been mistaken for a twentieth-century laptop computer – gave him a reassuring smile.

'Ready?' he asked.

There were times when the old clicheґs were the best ones.

'Ready as I'll ever be,' Poole answered.

Slowly, the light faded – or seemed to. A great silence descended, and even the gentle gravity of the Tower relinquished its hold upon him. He was an embryo, floating in a featureless void, though not in complete darkness.