...a short story written in 1962, depicts life in an eerie Panopticon world, a city that resembles modern London or New York except for the alien towers of smooth metal that hang inexplicably from the sky. Spaced a few blocks apart, these structures give their inhabitants, mysterious "watchers," clear lines of sight down onto the streets and rooftops of the metropolis. The city folk seem accustomed to the strange sky-turrets and try to lead normal lives in spite of them. Nevertheless, the presence of so much silent power overhead inevitably affects politics and mores.
The watchers are a passive lot; most days no visible activity takes place in the towers. However, on rare occasions movements can be glimpsed behind the semi-transparent windows. When this happens the city dwellers become fretful, avoid conversations, and try to stay indoors as much as possible. No one has actually seen a watcher, only the shadowy gestures overhead, but rumors abound that the watchers have influence with the city's main political body, called The Council. The Council lays down edicts about who can be romantically involved with whom, and the degree to which people can publicly assemble in large numbers.
The plot commences when a character named Renthall petitions the Council for an outdoor party, or fete, in a particular vacant city block in open view of the towers. The response from the Council's emissaries is furtive, bureaucratic, and heavy with innuendo and veiled threats. Renthall begins to be personally shunned. Through his innocent-sounding request he hopes to glimpse the inner working of the murkily-understood Council, and even better, to find out once and for all its connections to the watchers. Ballard creates a mood of danger all out of proportion to the innocuousness of Renthall's proposal--what is it, exactly, that the watchers aren't supposed to see?
The story has twists but let's not spoil them, except to say that in Ballard's fiction the line between personal and consensual paranoia can be blurry. And fortunately it's all a story and has no bearing on the modern world.
Update: The "modern world" link above went to a page that has since been removed. This thread quotes liberally from it even though the link is dead there, too. See also.