The Situationist City, by Simon Sadler MIT Press, 233pp, £24.95 in UK.Book Service: to order this book and have it sent directly to your home or office, call The Irish Times Book Service at 1850 30 60 60

By the time of the demise of the now mystique-laden Situationist International (SI) in 1972, this highly politicised art movement had become trapped in its own autocracy and revolutionary rhetoric. Yet while Situationism may not have produced much memorable art, it was the last 20th-century European movement which could be termed avant garde, and its activities and theorising influenced a generation and more of artists, architects, social theorists, hard-leftists and French intellectuals.

Sadler's book, though academic in form, is actually a highly amusing account of the founding principles of the Situationists. He has sifted through the early mass of material they published on urban planning, architectonics and industrial design under the Alexandria Library imprint of the SI.

It was an unlikely confederation that first convened in a small, remote bar in Italy in July 1957: delegates from the left-wing, conceptual, Paris-based Lettrist group (headed by Guy Debord, author of the influential Society of the Spectacle, who committed suicide in 1994), the International Movement for an Imaginist Bauhaus (led by expressionist, Asger Jorn), and the London Psychogeo graphical Association, represented by its only known member, Ralph Rumney. One strand of Situationist urban theory emerged from "cognitive mapping"; a "psychogeography" intuited from aimless "derives", or drifts, through the city - often favouring the louche ambience of certain old districts. The emphasis was on individuality and mobility. Situationists volubly opposed Le Corbusier's sterile, dehumanising, rationalist urban planning in which "an entire generation of the working class has been interred", and excoriated the high-rises as driven by "the most ferocious economic speculation and obtuse political inefficiency".

Certainly, the Situationist city would bear little resemblance to the classical mnemonic city, with its monuments and sites. The SI frequently cited the Paris Commune artists, led by Gustave Courbet, and their destruction of the Napoleonic Vendome column. More radical Situationists suggested that churches be "erased or emptied of significance", even that graveyards be emptied of corpses and headstones as "a hideous survival of past alienation".

Architecturally, their exemplars were bizarre: Ferdinand Cheval's wild Palais Ideal in Hauterives, King Ludwig II's Grotto of Venus at Linderhof, or the visionary cityscape paintings of Piranesi, de Chirico and John Martin. But they had more focused sympathies with Alison and Peter Smithson's "cluster cities", or the "labyrinthine clarity" of Aldo van Eyck's Amsterdam Children's Home. They also re-examined Fourier's unitary architecture of the 19th century, and the macquettes of Dutch Situationist Constant Nieuwenhuys were once written off as "phalansteries for the love generation".

While Constant's mega structures inspired much science fiction, most of them remained just that: sketches, maquettes and photomontages. Yet his New Babylon was the most realised form of Situationist "unitary urbanism". Wildly inspired by new engineering and materials, he envisaged continuous, radically decentred, reticular structures, often on pillars sixteen metres high, spreading across the landscape.

Internally, they would reflect Levi-Strauss's "structured cultural processes" and "patterns of association" in a playful, dizzying, frequently changing labyrinth of ideal social spaces for a "post-capitalist" age - when technology would render cities, and indeed work, unnecessary.

Typically, Constant was expelled from the SI in 1960 for reformist tendencies - more revolutionary Situationists correctly recognised that technology was consolidating, rather than undermining, the ruling class. Cons tant's rueful analysis in 1996 was that, at the end of the day, "automation, rather than bringing freedom, has resulted in poverty and boredom".

The Situationists emerge from this book as majestically preposterous but always inspiring: from Ivan Chtcheglov's visionary rhetoric to Asgar Jorn's proposals for an Institute of Contemporary Vandalism. It's a pity the illustrations aren't better printed, as this book sharpens one's perception of a city, and repoliticises it in very peculiar ways.