Here, for time travellers, is the whack-job spirit of ’68 in distillate form, paperbound and reissued in facsimile (with some exculpatory, older and wiser material fore and aft). Adhocism (re)captures with magical realism the boldness and silliness of its day.  This was the day when ‘new media’ meant colour television.

Younger readers may need more instruction on the nature of this spirit. Students in Paris hurled St Germain cobblestones at gendarmes in clouds of teargas and students at Hornsey College of Art sat in to protest I cannot quite remember what in clouds of pot smoke. The Parisians read Guy Debord on situationism, the Hornseyites drooled over nudes in the International Times. Meanwhile, students in architecture schools fretted about ‘coherent articulation with diverse subsystems’.

Although the original was not published until 1972, its co-author Charles Jencks claims to have coined the term ‘adhocism’ four years earlier, perhaps in a cloud of pot smoke while listening to the Beatles’ White Album and admiring its Richard Hamilton sleeve. Since charming fabulation, cosmic speculation, glazed theorising, bizarre reference and brazen self-quotation are very much Jencks’s métier, this might or might not be true. No matter, Adhocism was one of the great architecture books of its day.  And for connoisseurs of techno-bohemianism, might yet become one again.

It is an argument for improvisation and libertarianism in building design, an energetically muddled rebuttal of high modernism’s inflexible geometry and equally inflexible social theories. Here, in grainy black and white, you find (as exemplars of longed-for architectural freedoms) images of Soviet Mil Mi-10 skycrane helicopters lifting prefabs, a hip-flask disguised as a learned tome, a lady in Margate who lived in a Obus and (I specially like this one) ‘a chair no longer adequate as a seat becom[ing] something else’.

Adhocism is a sourcebook of ideas as much as Stuart Brand’s Last Whole Earth Catalog of 1971 (described by Steve Jobs as an ur-Google) was a sourcebook of useful stuff. It has the tone and texture of an ambitious seminar at the Architectural Association where the amiable Jencks was once one of the fixtures and fittings. It inspired for good or bad — I think bad — a generation.

But Jencks was not alone in his valorisation of tat. Another comparator was Victor Papanek’s Design for the Real World, also published in 1971. Papanek rejected high-finish, high-profit corporate design in favour of inspired re-use: so, instead of Mad Men surrounded by slick mid-century Modern in Manhattan, you were presented with pictures of Amazonian tribal folk in Xingu National Park ingeniously recycling grungey tinnies.

But there were other precedents too.  Gaudi used broken crockery. And there was Marcel Duchamp, of course. His re-appropriation of industrial products in the Twenties was absurdism’s finest hour. While in Italy, the designer Achille Castiglione had in the Fifties raided factory parts bins to make almost surreal furniture and lighting. Castiglione’s successor was the influential Italian anti-design movement which fought ferocious Seventies battles with the Milanese furniture industry. Today, you could cite Berlin’s refurbished Neues Museum or New York’s ingenious Highline linear urban park, a repurposed overhead railway, as examples of the adhoc genre.

Adhocism would be merely a quaint period piece were it not for the intellectual space trip Charles Jencks soon undertook after its publication. In 1977 there appeared his Language of Post-Modern Architecture, the first coherent attempt to describe a tacky global fad which bigged-up sub-adult decoration and dumbed-down intelligent building design. In Adhocism we can see many of the sources and inspirations of what was to come.

Forty years on, what was to come has now gone. Read Adhocism now to get a sense of the future that was.