'Strike me sir,' the old attendant coughs, 'doesn't look much like a library from this angle, does it?'

'No it doesn't,' I agree, watching a dozen men wheel some great pumping apparatus across the debris-strewn floor of the hall in front of us. 'Are you quite sure this is the right floor?'

He checks his floor indicator, thumping the dial with one arthritic fist. 'Sure as I can be, sir.' He digs out a pair of spectacles and peers again at the indicator. An explosion in the wreckage of pipes and girders sends up a roll of black smoke and sparks; men nearby jump for cover. A man wearing a tall hat and bright yellow uniform sees us and waves a megaphone. He steps over some bodies on stretchers and approaches us.

'You there!' he shouts. 'What the hell do you think you're doing, eh? Looters? Ghouls? Eh? Is that it? Get on your way at once!'

'I'm looking for the Third City Records and Historical Materials Library,' I tell him calmly. He waves his megaphone at the chaotic scene behind him.

'So are we, you idiot! Now fuck off!' He jabs the megaphone in the direction of my chest and storms off, tripping over one of the bodies on the stretchers and then running over to direct the men manoeuvring the giant pump. The old attendant and I look at each other. He closes the doors.

'Rude bugger, eh, sir?'

'He did seem a little upset.'

'Train deck sir?'

'Hmm? Oh, yes. Please.' I hold onto the rattling brass rail again as we descend. 'I wonder what happened to the library?'

The old man shrugs. 'Goodness knows, sir. All sorts of funny things happen in these higher reaches. Some of the things I've seen ...' He shakes his head, whistles through his teeth. 'You'd be amazed, sir.'

'Yes,' I admit ruefully, 'I probably would.'

At the rackets club in the afternoon I win one game, lose the other. The aircraft and their strange signals are the only topic of conversation; most of the people at the club - professionals and bureaucrats to a man - regard the odd fly-past as an unwarranted outrage about which Something Must Be Done. I ask a newspaper journalist if he has heard anything about a terrible fire on the level where the Third City Library was supposed to be, but he hasn't even heard of the library, and certainly not of any upper-structure disaster. He will check.

From the club I phone Repairs and Maintenance and tell them about my television and telephone. I eat at the club and go to a theatre at night; an uninspired production about a signalman's daughter who falls in love with a tourist who turns out to be a railway boss's son, engaged and having one last fling. I leave after the second act.

At home, as I undress, a small crumpled piece of paper falls from a pocket in my coat. It is the smudged diagram the hospital receptionist drew for me to show me the way to Dr Joyce's office. It looks like this:

I stare at it, vaguely troubled. My head feels light and the room seems to tip, as though I am still in the decrepit L-shaped elevator with the old attendant, completing another unscheduled and dangerous lift-shaft manoeuvre. For a moment my thoughts feel scrambled, mixed up like the smoke signals trailed by the strange flight of planes this morning (and for an instant, dizzy and swaying, I myself seem somehow clouded and formless, like something chaotic and amorphous, like the mists which curl amongst the snagging complexity of the high bridge, coating the layers of ancient paint on its girders and its beams like sweat).

The telephone rings, snapping me out of this odd moment; I lift the receiver only to hear the same, curious, regular beeping at the other end. 'Hello? Hello? ' I say. Nothing.

I put it down. It rings again and the same thing happens. I leave it off the cradle this time and cover the earpiece with a cushion. I don't even try the television - I know what I'll see.

As I head for bed, I realise I am still holding the small piece of paper. I throw it into the waste-bin.

At my back lay the desert, ahead the sea. One golden, one blue, they met like rival modes of time. One moved in the immediate, sparkling in troughs and crests, lifting white and falling, beating the shelf of sand, and the tide as breath . . . the other moved more slowly, but as surely, the tall advancing waves of sand stroked over the waste by the combing hand of the unseen wind.

Between the two, half submerged by each, the ruined city.

Abraded by both sand and water, caught like something soft between two meshing iron wheels, the stones of the city submitted to the agents of the wind.

I was alone, and walked through the midday heat, a white ghost billowing through the tumbled wreckage of the shattered buildings. My shadow was at my feet, beneath me; invisible.

The rose-red stones were jumbled and askew. Most of the streets were gone, long ago buried under the soft encroaching sands. Ruined arches, fallen lintels, collapsed walls littered the slopes of sand; at the scalloped edge of shore, brushed by the waves, more fallen blocks broke the incoming waves. A little out to sea, tilted towers and the fragment of an arch rose from the waters, sucked at by the waves like the bones of the long-drowned.

On the worn stones over empty doors and sand-filled windows, friezes of figures and symbols had been carved. I inspected these curious, half-legible images, attempting to decipher their linear patterns. The wind-blown sand had eroded some of the walls and beams until the thickness of stone was less than the depth of the chiselled symbols; blue sky shone through the blood-red rock. 'I know this place,' I said to myself. 'I know you,' I said to the silent wreckage.

A huge statue stood apart from the main area of the city's ruins. The thick-set trunk and head of a man, perhaps three or four times life-size, it faced along a diagonal between the line of foam-washed beach and the centre of the silent ruins. The statue's arms had fallen or been broken off long ago; the stumps worn smooth by the wind and sand. One side of the massive body and head showed the accumulated effects of the scouring wind, but on the front, and the other side, this figure's details were still apparent; a naked torso, big-bellied, but the upper chest covered in chains and jewels and rope-thick necklaces; the great head, bald but crowned, ear heavy with rings, nose studded. The expression on that time-worn face was one which, like the graven symbols, I could not translate; perhaps cruelty, perhaps bitterness, perhaps a callous disregard for all things, save sand and wind.

'Mock? Mocca?' I found myself whispering, gazing up at the bulbous stone eyes. The giant offered no help. Names too became worn away, however slowly; at first altered, then reduced, then forgotten.

On the beach before the city, some way from the statue's stony gaze, I found a man. He was small and lame and hunched over, and he stood up to his knees in the shallow surf, the waves washing round the dark rags he wore, and he beat at the surface of the water with a heavy lash of chains, cursing all the while.

His head was bowed under the weight of his deformed back; long, filthy hair hung down in tight tangles to the chopping waves, and sometimes, like a sudden grey-white hair erupting from the centre of this dark mass, a long strand of spittle would drop towards the waves, and float away.

All the time his right arm rose and fell, whipping at the sea with his flail, a short heavy thing with a shining wooden handle and a dozen glistening, rusting lengths of iron chain. The waters around him frothed and bubbled under this steady and unceasing attack, and clouded with the grains of sand disturbed from the slope beneath.

The hunched man stopped his flogging for a moment, shifted - crablike - a step to one side, wiped his mouth with one cuff, then resumed, muttering all the time as the heavy chains rose, fell, splashed. I stood on the shore behind him, watching, for a long time. He stopped again, wiped his face once more, then took another step to the side. The wind blew his ragged clothes, briefly lifted his oily, tangled hair. My own loose garment flapped in the same gust, and he may have heard the noise over the falling surf, for he did not immediately resume his labours. His head moved slightly, as though to catch some faint sound. He seemed to try to straighten his twisted back, but then gave up. He turned slowly round in a succession of tiny shuffling steps - as though his feet were hobbled on a short chain - until he faced me. He brought his head up, slowly, until he could look at me, then stood, the waves still breaking around his knees, the flail dangling in the water from one gnarled hand.