A cloudless sky, as dull as the air over a cold vat, lay across the concrete walls and embankments of the development project. At dawn, after a confused night, Laing went out on to his balcony and looked down at the silent parking-lots below. Half a mile to the south, the river continued on its usual course from the city, but Laing searched the surrounding landscape, expecting it to have changed in some radical way. Wrapped in his bath-robe, he massaged his bruised shoulders. Although he had failed to realize it at the time, there had been a remarkable amount of physical violence during the parties. He touched the tender skin, prodding the musculature as if searching for another self, the physiologist who had taken a quiet studio in this expensive apartment building six months earlier. Everything had started to get out of hand. Disturbed by the continuous noise, he had slept for little more than an hour. Although the high-rise was silent, the last of the hundred or so separate parties held in the building had ended only five minutes beforehand.

Far below him, the cars in the front ranks of the parking-lot were spattered with broken eggs, wine and melted ice-cream. A dozen windscreens had been knocked out by falling bottles. Even at this early hour, at least twenty of Laing's fellow residents were standing on their balconies, gazing down at the debris gathering at the cliff-foot.

Unsettled, Laing prepared breakfast, absent-mindedly pouring away most of the coffee he had percolated before he tasted it. With an effort he reminded himself that he was due to demonstrate in the physiology department that morning. Already his attention was fixed on the events taking place within the high-rise, as if this huge building existed solely in his mind and would vanish if he stopped thinking about it. Staring at himself in the kitchen mirror, at his wine-stained hands and unshaven face with its surprisingly good colour, he tried to switch himself on. For once, Laing, he told himself, fight your way out of your own head. The disturbing image of the posse of middle-aged women beating up the young masseuse anchored everything around him to a different plane of reality. His own reaction-the prompt side-step out of their way-summed up more than he realized about the progress of events.

At eight o'clock Laing set off for the medical school. The elevator was filled with broken glass and beer cans. Part of the control panel had been damaged in an obvious attempt to prevent the lower floors signalling the car. As he walked across the parking-lot Laing looked back at the high-rise, aware that he was leaving part of his mind behind him. When he reached the medical school he walked through the empty corridors of the building, with an effort re-establishing the identity of the offices and lecture theatres. He let himself into the dissecting rooms of the anatomy department and walked down the lines of glass-topped tables, staring at the partially dissected cadavers. The steady amputation of limbs and thorax, head and abdomen by teams of students, which would reduce each cadaver by term's end to a clutch of bones and a burial tag, exactly matched the erosion of the world around the high-rise.

During the day, as Laing took his supervision and lunched with his colleagues in the refectory, he thought continually about the apartment building, a Pandora's box whose thousand lids were one by one inwardly opening. The dominant tenants of the high-rise, Laing reflected, those who had adapted most successfully to life there, were not the unruly airline pilots and film technicians from the lower floors, nor the bad-tempered and aggressive wives of the well-to-do tax specialists on the upper levels. Although at first sight these people appeared to provoke all the tension and hostility, those really responsible were the quiet and self-contained residents, like the dental surgeon Steele and his wife. A new social type was being created by the apartment building, a cool, unemotional personality impervious to the psychological pressures of high-rise life, with minimal needs for privacy, who thrived like an advanced species of machine in the neutral atmosphere. This was the sort of resident who was content to do nothing but sit in his over-priced apartment, watch television with the sound turned down, and wait for his neighbours to make a mistake.

Perhaps the recent incidents represented a last attempt by Wilder and the airline pilots to rebel against this unfolding logic? Sadly, they had little chance of success, precisely because their opponents were people who were content with their lives in the high-rise, who felt no particular objection to an impersonal steel and concrete landscape, no qualms about the invasion of their privacy by government agencies and data-processing organizations, and if anything welcomed these invisible intrusions, using them for their own purposes. These people were the first to master a new kind of late twentieth-century life. They thrived on the rapid turnover of acquaintances, the lack of involvement with others, and the total self-sufficiency of lives which, needing nothing, were never disappointed.

Alternatively, their real needs might emerge later. The more arid and affectless life became in the high-rise, the greater the possibilities it offered. By its very efficiency, the high-rise took over the task of maintaining the social structure that supported them all. For the first time it removed the need to repress every kind of anti-social behaviour, and left them free to explore any deviant or wayward impulses. It was precisely in these areas that the most important and most interesting aspects of their lives would take place. Secure within the shell of the high-rise like passengers on board an automatically piloted airliner, they were free to behave in any way they wished, explore the darkest corners they could find. In many ways, the high-rise was a model of all that technology had done to make possible the expression of a truly "free" psychopathology.

During the long afternoon Laing slept in his office, waiting until he could leave the medical school and return home. When he left at last he drove at speed past the half-completed television studios, and then was held up for five minutes by a line of bulk-cement carriers entering the construction site. It was here that Anthony Royal had been injured when his car had been crushed by a reversing grader-it often struck Laing as ironic, and in a way typical of Royal's ambiguous personality, that he should not only have become the project's first road casualty, but have helped to design the site of the accident.

Annoyed by the delay, Laing fretted at the wheel. For some reason he was convinced that important events were taking place in his absence. Sure enough, when he reached the apartment building at six o'clock he learned that a number of fresh incidents had occurred. After changing, he joined Charlotte Melville for drinks. She had left her advertising agency before lunch, worried about her son.

"I didn't like him being on his own here-the babysitters are so unreliable." She poured whisky into their glasses, gesturing with the decanter in an alarmed way as if about to toss it over the balcony rail. "Robert, what is happening? Everything seems to be in a state of crisis-I'm frightened to step into an elevator by myself."

"Charlotte, things aren't that bad," Laing heard himself say. "There's nothing to worry about."

Did he really believe that life here was running smoothly? Laing listened to his own voice, and noticed how convincing he sounded. The catalogue of disorder and provocation was a long one, even for a single afternoon. Two successive groups of children from the lower floors had been turned away from the recreation garden on the roof. This walled enclosure fitted with swings, roundabouts and play-sculptures had been specifically intended by Anthony Royal for the amusement of the residents' children. The gates of the garden had now been padlocked, and any children approaching the roof were ordered away. Meanwhile, the wives of several top-floor tenants claimed that they had been abused in the elevators. Other residents, as they left for their offices that morning, had found that their car tyres had been slashed. Vandals had broken into the classrooms of the junior school on the 10th floor and torn down the children's posters. The lobbies of the five lower floors had been mysteriously fouled by dog excrement; the residents had promptly scooped this into an express elevator and delivered it back to the top floor.

When Laing laughed at this Charlotte drummed her fingers on his arm, as if trying to wake him up.

"Robert! You ought to take all this seriously!"

"I do…"

"You're in a trance !"

Laing looked down at her, suddenly aware that this intelligent and likeable woman was failing to get the point. He placed an arm around her, unsurprised by the fierce way in which she embraced him. Ignoring her small son trying to open the kitchen door, she leaned against it and pulled Laing on to herself, kneading his arms as if trying to convince herself that here at last was something whose shape she could influence.

During the hour they waited for her son to fall asleep her hands never left Laing. But even before they sat down together on her bed Laing knew that, almost as an illustration of the paradoxical logic of the high-rise, their relationship would end rather than begin with this first sexual act. In a real sense this would separate them from each other rather than bring them together. By the same paradox, the affection and concern he felt for her as they lay across her small bed seemed callous rather than tender, precisely because these emotions were unconnected with the realities of the world around them. The tokens that they should exchange, which would mark their real care for each other, were made of far more uncertain materials, the erotic and perverse.

When she was asleep in the early evening light, Laing let himself out of the apartment and went in search of his new friends.

Outside, in the corridors and elevator lobbies, scores of people were standing about. In no hurry to return to his apartment, Laing moved from one group to another, listening to the talk going on. These informal meetings were soon to have an almost official status, forums at which the residents could air their problems and prejudices. Most of their grievances, Laing noticed, were now directed at the other tenants rather than at the building. The failure of the elevators was blamed on people from the upper and lower floors, not on the architects or the inefficient services designed into the block.

The garbage-disposal chute Laing shared with the Steeles had jammed again. He tried to telephone the building manager, but the exhausted man had been inundated with complaints and requests for action of every kind. Several members of his staff had resigned and the energies of the remainder were now devoted to keeping the elevators running and trying to restore power to the 9th floor.