While noting the view of technology as an agent that acts on society, Carroll Pursell, who is professor of history of technology and science at Case Western Reserve University, says, "tools and processes that we use are a part of our lives, not merely instruments for our purpose". His emphasis strikes me as more helpful in understanding current problems that have technological components (and which does not?) than does the personification implied by "technology versus society", where "society" means "us".

The earlier centuries are dealt with very readably: one learns that the pit saw came from England with the Pilgrims, while the corresponding water-driven sawmill was brought by the Dutch in 1623, evolving little in the two centuries until the English circular saw, of American Revolution vintage, arrived in 1814. The bandsaw, now ubiquitous, was an American patent of 1869. The huge American supply of lumber and the demand for boards reputedly drove this inventiveness; still, 250 years from the pitsaw to the bandsaw does sound leisurely.

In 1841 parliament heard that the American axe could fell three trees to one as compared to the English axe; no doubt the incentive to invention came from felling pine trees with imported axes hitherto mostly used on English oak. Though the pace of response seems slow, the distinctive American axe became an icon of frontier pride. The story of carding, spinning and weaving as told with emphasis on social aspects and sacrifice of mechanical detail adds much to the familiar standard history of mechanisation of textile manufacture.

Later centuries are harder for Pursell to deal with synoptically because of the increased complexity of maritime commerce and because some major innovations depend on thermodynamics, electricity, electromagnetism, chemistry or biology - in short scientific literacy enters. As the technical background is slighted, so the interpretations of social significance become less compelling. Take the theory that labour-saving devices were little valued in the presence of slave labour. Did the postmedieval mechanical devices, attributed to conscious pursuit of labour saving, really gestate differently from those of classical times?

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Innovation did accelerate in modern times (so did population growth), but was slave labour a disincentive to labour saving? In communities without slave labour, were there more labour-saving inventions? Think of the greatest labour-intensive activity of antiquity, pyramid building; whip-driven slaves were available, but surely much store was set by the improvement of tools for quarrying, masonry, surveying, earth moving and transportation. Mining, smelting, working of copper, manufacture of rope and sails, construction of harbours, docks, cranes and roads, axes, hammers, saws, chisels, planes, augers, scrapers and other woodworking tools, tool maintenance, heavy sleds and rollers, and many other technologies were brought close to perfection under the circumstances. It is hard to see the cost of acquiring, training, and feeding slaves as a disincentive to labour-saving innovation. The disrespect for manual labour attributed to the Greeks, and explained by the availability of slaves, is a myth due to the teacher Plato, perpetuated by later authors who also did not like to dirty their hands (save with ink). Other Greek citizens were responsible for the triremes, boatsheds, rigging, temples and other structures, mines, metallurgy, tunnels, water supply, canals, tools, weapons, industrial processes and other manual/mental activities, none of whom Plato would have respected. "He who can, does," said Shaw. "He who cannot, teaches."

A seminar debate on slave labour might engender a feeling for the relevance of the technical details, a helpful experience for students thinking later about current problems with technological content. Some might also glimpse the intellectual stature of the despised hand-brain activity, and even catch a glimmer of the profundity of thought required to understand and cope with the design and construction of, say, a carding machine. What was hard about that?

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Ernest Braun, who is a visiting professor at the Centre for Technology Strategy at the Open University, and emeritus from Aston University, says social harmony requires plenty of equal-opportunity jobs; reasonably narrow income distribution; good social security, medicine and retirement; good housing, transport, and leisure amenities; good cultural pursuits; high regard for the natural environment; pleasing urban surroundings; and the usual freedoms, equalities, and access to education. I find this list lacking in attention to family values and job satisfaction, while the 1995 Beijing conference has reminded us that social harmony will require more than just listing "equality of sexes, races, and other groupings".

"One of the main results of such a state (of social harmony)," says Braun, "should be the virtual absence of criminality and a considerable sense of cooperation. Indeed there would be very much more stress on cooperation than on competition, or equal opportunity, rather than on privilege, on true achievement rather than on status."

Individuals tend to have differing goals but if Braun's state were momentarily achieved - somewhere - would the social harmony prove stable? Perhaps those who are slightly better off would like to advance; perhaps migrants to this utopia would settle for less than the minimum wage; and change might soon be wrought by population growth or natural disasters. Meanwhile Braun proposes to foster his state of social harmony by influencing government policy on economics and technology.

The possibility that society is on an unaimed trajectory whose midcourse corrections will merely be sufficient unto the day suggests changes to Braun's prescriptions for regulation of technology, for example the one that "only those technologies will be selected that can make money in the marketplace". The initial care and feeding of a new advance in technology is often not determined in the marketplace. The Internet, which is remaking much of society, worldwide, grew to its late teens without the market, satellite communication got off the ground without investment, and many commercial aircraft originated as military designs without the market, while innumerable small inventions on the farm, in the home, in the workshop, and in sports originated without market midwifery. When the market does play a role, it often gambles that money may be made, with no certainty that it can or will. Indeed, the market sorts winners from losers after the fact, rarely selecting those infant technologies that can make money.

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Who will do the selecting referred to by Braun - the technology policy managers? The back cover of the book suggests improving policy "so that only technologies beneficial to society receive public support". Life just does not seem to work that way; the pursuit of environmentally nonbeneficial enterprises (a large fraction of all large-scale technologies, including electricity, water supply, sewage, agriculture, housing, textiles, mining, and forestry) evolves without selection or rejection by policy controllers. The environmental disasters associated with irrigation and dams are perhaps not to be blamed on technology at all (after all, our food and water depend on irrigation and dams) but on entrepreneurs - or policy makers.

Jean Gimpel, known as the author of The Cathedral Builders and The Medieval Machine: The Industrial Revolution of the Middle Ages first chronicles the failures of high technology including computers, flight, synthetics and pharmaceuticals, introduced by a searing review of overoptimistic futurology of the 1970s. The numerous alarming episodes are packaged in dire page-sized doses. It is all true, but others think it is normal for technology to advance over the wreckage of tests to destruction. Gimpel holds that the growth, maturity and decay of previous civilisations is cyclic and has averaged about 250 years, introducing many pithy historical parallels to illustrate. Of course, analogies are always imperfect. Nevertheless, one can only agree that exponential increase cannot continue, if indeed it is now continuing. The population explosion alone guarantees collision with a resistant ceiling. Whether industrial society levels off or collapses may be beyond human choice. Gimpel himself has the stalwart optimism of a phoenix.

Ron Bracewell is Terman professor of electrical engineering emeritus, Stanford University.