WHAT would an archaeologist digging in the remains of our cities two millennia from now make of our civilisation?

That鈥檚 a fine question, posed by long-time US archaeologist Eric Cline in the stimulating epilogue to his new book, Three Stones Make a Wall. Assuming that our noticeboards and signposts, if not our long-vanished emails and websites, are still decipherable in AD 4000, most large urban structures, such as highways, bridges, schools and even archaeological museums, should be easy enough to figure out.

But what about what Cline labels 鈥渢he ubiquitous rectangular blobs of metal, plastic, glass and circuitry that seem to be associated with every skeleton鈥�, frequently found clutched in a bony hand? Will future diggers know that these were once communication devices?

And what of the still more puzzling shrines or temples 鈥渃omplete with a goddess wearing a crown and with flowing locks鈥�, located on virtually every street corner? 鈥淚 think there is a good chance of misidentifying Starbucks as a religion,鈥� jokes Cline. After all, a religious purpose is the typical explanation put forward by today鈥檚 archaeologists for anything incomprehensible that they find in ancient ruins.

Most of Cline鈥檚 book deals with the stories of dramatic discoveries since archaeological excavation became methodical, beginning at Herculaneum and Pompeii in the 18th century. These are selected from around the Mediterranean and a few other parts of Europe, the Americas, Egypt and the Middle East, with occasional forays into the rest of Africa and Asia. For reasons that aren鈥檛 explained, Russia, the Indian subcontinent, Japan, Australia and Polynesia don鈥檛 feature.

Interwoven with these stories are the careers and colourful personalities of some well-known archaeologists, such as Heinrich Schliemann at Troy and Mycenae, Arthur Evans at Knossos, Howard Carter at Tutankhamun鈥檚 tomb, Leonard Woolley at Ur, and the Leakey family in east Africa. There are some more recent pioneers too: underwater archaeologist George Bass, the excavator of Bronze Age shipwrecks in the Mediterranean, and David Stuart, Mayan script decipherer and the youngest person to receive a MacArthur Fellowship, at just 18.

鈥淲hat of the puzzling shrines or temples with a goddess wearing a crown, on every street corner?鈥�

Both the discoveries and the discoverers are illuminated by gritty fieldwork recounted from Cline鈥檚 experience at sites around the eastern Mediterranean, such as the ancient city of Megiddo in Israel, known as Armageddon to the Greeks. This area was the focus of his valuable 2014 book about the Bronze Age, 1177 BC: The year civilization collapsed.

The mix is an enjoyable and wide-ranging one. That said, the most original and clearly scientific sections of Three Stones Make a Wall are four chapters prompted by the questions non-archaeologists are wont to ask. How do you know where to dig? How do you know how to dig? How old is this and why it is it preserved? Do you get to keep what you find?

Cline patiently explains. Where to dig depends on the surveying methods. These range from people on foot fanatically scouring areas for artefacts, to aircraft scanning jungle terrain using aircraft equipped with laser tech (lidar), to the sophisticated interpretation of satellite images by individual archaeologists.

In 2010, for example, Cline and fellow academic Sarah Parcak purchased some Quickbird satellite imagery of the area around Tel Megiddo. 鈥淎lmost immediately,鈥� writes Cline, 鈥渨e saw the outlines of what looked like a large building in a field right next the ancient mound.鈥� The images had pinpointed the exact spot Israeli archaeologist Yotam Tepper had earlier proposed as the probable location of the camp of the sixth Roman legion during the 2nd century AD.

The two also found 鈥渁n almost perfect match with other Roman camps鈥�, like those built around the hilltop site of Masada, a fortress besieged by the Romans around AD 73. They shared the images with Tepper and his collaborator, who carried out remote-sensing of the site at Tel Megiddo, including ground-penetrating radar and electromagnetic surveys. Subsequent excavations revealed Roman-period coins, pieces of armour and roof tiles stamped with insignia of the sixth legion: it was definitely their camp.

As for the dating of artefacts, Cline rattles through radiocarbon and potassium-argon analysis, rehydroxylation, pottery typology, thermoluminescence and dendrochronology. However, he stresses, archaeologists must admit 鈥渁 willingness to acknowledge that none of it is fixed in stone鈥�.

For example, rehydroxylation can estimate the age of pottery on the basis of the rate at which it absorbs water after its original firing. But when it was applied to a medieval brick from the UK city of Canterbury, it gave an age of about 66 years. The brick turned out to have been accidentally re-fired when Canterbury was bombed in the second world war.

As for the question of who keeps what, finders are no longer keepers. 鈥淣ot only don鈥檛 I get to keep what I find,鈥� observes Cline, 鈥淚 don鈥檛 think that other people should collect such items either.鈥� The consensus among scholars, he says, is that there is a direct correlation between private collecting and the looting of ancient sites 鈥� as the recent destruction of ancient Syrian sites by ISIS shows so painfully.

It is difficult to disagree. And yet, how very much poorer would the world鈥檚 great archaeological museums be without the past donations of private (and often none too scrupulous) collectors.

This article appeared in print under the headline 鈥淩aiders of the lost phone鈥�

, Reaktion Books

IN 2002, two NASA satellites nicknamed 鈥淭om鈥� and 鈥淛erry鈥� were charting Earth鈥檚 gravitational field, as part of the Gravity Recovery and Climate Experiment. As they moved in the same polar orbit, the distance between them was monitored to an accuracy of 10 micrometres, a tenth of the width of a human hair. When either satellite flew over an area of increased gravity, it would speed up slightly and the distance would increase or decrease.

The experiment鈥檚 vital result is recounted in Satellite, Doug Millard鈥檚 accessible and superbly illustrated book, which tracks the history of this amazing extension to our lives. By combining the changes in distance between the satellites with their respective positions 鈥� measured by GPS 鈥� it was possible to build a detailed map of Earth鈥檚 gravity field, writes Millard, deputy keeper of technologies and engineering at London鈥檚 Science Museum.

Satellites have a long history, with Isaac Newton the first to imagine one in Principia Mathematica (1687). He envisioned a cannon projecting a ball from a mountaintop with ever more force. In the end, noted Newton, the ball would reach beyond Earth鈥檚 circumference, retain its velocity and 鈥渄escribe the same curve over and over鈥�.

But Newton had no concept of a satellite鈥檚 usefulness. That came in 1869, when Edward Everett Hale suggested in his story, The Brick Moon, that they could be used as an orbiting reference point for measuring longitude.

By the early 20th century, rocket pioneers like Robert Goddard, Hermann Oberth and Konstantin Tsiolkovsky were showing how satellites could be launched, and in 1944, a German military team led by Wernher von Braun fired a V2 missile to an altitude of some 180 kilometres. Inspired by the V2, in 1945 Arthur C. Clarke, then a Royal Air Force radar engineer, predicted that it would take only three satellites in geostationary orbit, 36,000 kilometres above the equator, to handle Earth鈥檚 communications.

In the 1950s, the US and Soviet Union raced to launch a satellite. The Soviets won in 1957, marking the start of the space age. The name of their satellite, Sputnik, translated into 鈥渇ellow traveller鈥�, or companion to Earth. Fellow traveller was also cold-war speak for Communist sympathiser.

The triumph humiliated the US, provoking the country to set up NASA, launch Explorer (its first satellite) in 1958, establish the Apollo space programme in 1961, and Telstar, the first commercial communications satellite, in 1962.

Millard, who curated the Science Museum鈥檚 2015 hit Cosmonauts show, mixes technology with Russian, US and European politics to great effect. For example, his book includes an early 1960s photo of a US aircraft that could capture a capsule dropped by a US satellite, containing film of Earth鈥檚 surface. He quotes an off-the-record comment by President Lyndon Johnson about the secret film鈥檚 value: 鈥淲e were building things we didn鈥檛 need to build鈥� Because of satellites I know how many missiles the enemy has.鈥�

鈥淚saac Newton imagined satellites in Principia Mathematica, but had no concept of their usefulness鈥�

Today, everyone has access to detailed images of Earth鈥檚 surface. More than 1400 satellites, some 500 in geostationary orbit, predict weather and handle navigation, communications and TV broadcasting. But, says Millard, we must not depend on them completely. In 2009, a retired Russian satellite crashed spectacularly into a working US communications satellite. Indeed, tonnes of space junk threaten to degrade all satellite services.

Then there are solar flares, which caused electrical disruption in 1859 and 1921. In 2012, one just missed Earth. The price of our connected world is that the next big flare will produce chaos.

This article appeared in print under the headline 鈥淐onnecting the world鈥�

by Jack Copeland, Jonathan Bowen, Mark Sprevak and Robin Wilson, Oxford University Press

DURING the 20th century, any book calling itself The Turing Guide would have been inconceivable. But in 2017 we have a massive and extraordinarily wide-ranging volume about the life, work and influence of mathematician Alan Turing. This is despite his achievements being shrouded in official and personal secrecy at the time of his death in 1954, aged 41, and for decades afterwards. The new guide is the work of four editor-writers: Turing historian Jack Copeland, computer scientist Jonathan Bowen, philosopher Mark Sprevak and mathematician Robin Wilson.

In the 1960s, Turing was known only to a few mathematicians, computer scientists and philosophers 鈥� and to one science-fiction writer, Arthur C. Clarke. In his 1962 book Profiles of the Future, Clarke showed himself well informed about the Turing test for machine 鈥渢hinking鈥�, noting that: 鈥淎n electronic brain that passed this test would, surely鈥� be regarded as an intelligent entity鈥� 鈥� like the computer HAL that Clarke would soon imagine in 2001: A Space Odyssey.

Turing encapsulated his own test in a humorous human-computer 鈥渃onversation鈥�, quoted in The Turing Guide. Human: 鈥淚n the first line of your sonnet which reads 鈥楽hall I compare thee to a summer鈥檚 day鈥�, would not 鈥榓 spring day鈥� do as well or better?鈥� Computer: 鈥淚t wouldn鈥檛 scan.鈥� Human: 鈥淗ow about 鈥榓 winter鈥檚 day鈥�? That would scan all right.鈥� Computer: 鈥淵es, but nobody wants to be compared to a winter鈥檚 day.鈥�

But Clarke on Turing the man was (given the time of writing) much less well informed. He was a 鈥渂rilliant mathematician鈥� who 鈥渇irst indicated how thinking machines might be built鈥� and then 鈥渟hot himself a few years after publishing his results鈥�.

Only between the 1970s and 2000 did a truer picture of Turing start to emerge, with the gradual declassification of the UK鈥檚 wartime codebreaking effort at Bletchley Park, and the publication in 1983 of Alan Turing: The enigma. This was an eye-opening biography by Andrew Hodges, a mathematician and gay rights activist, who provides a brief foreword to The Turing Guide.

A man of parts

This new version of Turing came in three parts. First, there is the theoretical founder of modern computing, with his 1936 paper 鈥淥n computable numbers鈥�. Then, there is the brain of recent plays and movies, which mostly focus on his key role in codebreaking, beginning with cracking the Enigma code in 1941 using the bombe, a machine he co-invented. Last, we have the man convicted of homosexual practices in 1952 and forced to take female hormones, and who fatally ingested cyanide at home probably by biting into a poisoned apple: a possible, but certainly not provable, suicide.

In 2009, Turing received a posthumous apology from the prime minister for this shabby treatment; in 2012, an extensive centenary celebration; and in 2013, an official pardon from the Queen.

Today, he is widely known as an intellectual warrior and has become something of a cult figure. Steve Jobs wanted his company鈥檚 bitten-apple logo to be associated with Turing鈥檚 love of apples. And in 2015, staff at the UK鈥檚 monitoring centre GCHQ queued out of their Cheltenham building to get an exclusive GCHQ copy of a new biography, Prof: Alan Turing decoded, by his nephew John Dermot Turing, who contributes a chapter in the guide.

Turing still lacks the final accolade of a statue in central London to complement that of his ultimate boss, Winston Churchill, who called the codebreakers 鈥済eese that laid the golden eggs 鈥� but never cackled鈥�. As the editors write pointedly in their preface: 鈥淚t is no overstatement鈥� without Turing, the war would probably have lasted longer, and might even have been won by the Nazis.鈥�

A handful of the guide鈥檚 33 contributors worked at Bletchley and knew Turing personally. Their reminiscences can be fascinating, funny, even moving. Captain Jerry Roberts, for example, was a graduate student of French and German who worked on Tunny, Adolf Hitler鈥檚 code for communicating with his top commanders that Turing broke using a technique nicknamed 鈥淭uringery鈥�. Roberts writes:鈥滻 have a strong mental image of him walking along the corridor in one of Bletchley Park鈥檚 Huts. With his gaze turned downwards, he was a shy and diffident man, flicking the wall with his fingers as he walked鈥� he was not a warrior king. But at that juncture, he was the most influential man in Europe bar none, and we owe our freedom to him.鈥�

Mathematician Peter Hilton worked on Tunny as an 18-year-old undergraduate. He recalls the priceless story of how Turing unexpectedly volunteered for the local Home Guard so he could become a first-class shot with a rifle. However, when filling in the standard application, Turing took the logical precaution of writing 鈥淣o鈥� against the question: 鈥淒o you understand that, by enrolling in His Majesty鈥檚 Local Defence Volunteers, you render yourself liable for military discipline?鈥�

When he failed to show up for parades and was court-martialled, the colonel asked him: 鈥淒o you realise this is a very serious offence?鈥� Turing calmly referred to his application. The colonel read it, then said, apoplectically: 鈥淵ou were improperly enrolled. Get out of my sight!鈥�

On the German side, such military rigidity often supplied valuable clues to the British codebreakers. For instance, the tendency of Tunny operators to repeat a message that had gone wrong in transmission, without changing the wheel settings on their encryption machine, offered the codebreakers two not-quite-identical messages for comparative analysis. They termed these 鈥渄epths鈥�, as Copeland explains in his chapter, 鈥淭unny: Hitler鈥檚 biggest fish鈥�.

鈥淭uring was the most influential man in Europe bar none, and we owe our freedom to him鈥�

Of the book鈥檚 42 chapters, Copeland contributes eight that he wrote alone and eight written with others. Bletchley veterans aside, most contributors are, like the editors, academics working in mathematics, computer science, cognitive science, artificial intelligence, philosophy 鈥� and biology. Including the latter specialism was just as well because Turing鈥檚 final work, his 1952 theory of morphogenesis, concerned the chemical basis for the evolution of patterns in nature, such as animal stripes, and the concept of artificial life.

There are, meanwhile, plenty of surprises. For example, a literature professor describes Turing鈥檚 interest in the paranormal, which led him to claim in 1950 that 鈥渢he statistical evidence, at least for telepathy, is overwhelming鈥�; and there is Turing the composer, responsible for some of the earliest computer music, recorded by the BBC in Turing鈥檚 Manchester labs.

Meaning of genius

Has anything significant been omitted from this authoritative collection? More reflection about Turing鈥檚 impact on gay rights might have been welcome. So would a separate chapter on the nature of his 鈥済enius鈥�, given that the term is applied to Turing by so many of the contributors. Indeed, Copeland and Bowen finish their engaging and informative introductory chapter by describing Turing as a 鈥渟hy, gay, witty, grumpy, courageous, unassuming and wildly successful genius鈥�. Very true 鈥� but which of these adjectives also apply to other geniuses in mathematics, physics and invention, and which are unique to Turing?

Considering my admiration for most of the guide, it may seem odd to recommend Turing newcomers to start with Hodges鈥檚 book. But it makes sense: his biography has little mathematics, and largely non-technical accounts of codebreaking. The Turing Guide, on the other hand, varies enormously, from the wholly biographical to the highly technical 鈥� with the latter particularly apparent when describing Turing鈥檚 contribution to mathematics and codebreaking. Graduate to it.

Once you do, you will find the whole Turing (or as much as we can ever know). Inevitably for a collection and with someone of such diverse achievements, and unconventional personality and personal life, there will be many voices and angles on the same aspects of Turing, and repetition.

But it is, I think, pretty much the last word on the subject. And it will ensure that while we may never decode the whole of Turing鈥檚 mind, his name will never again be forgotten.

This article appeared in print under the headline 鈥淎ll around Turing鈥�

PICTURE a peace-loving Atlantic island ruled by reason. Its 54 cities are governed by educated officials and an elected-for-life prince. Although war hasn鈥檛 been abolished, it is used only as a last resort. People see no glory in fighting, and capture enemies rather than kill them. This is the original Utopia 鈥� the pagan, communist and pacifist world sketched out exactly 500 years ago in Thomas More鈥檚 eponymous work of fiction.

More鈥檚 book has exerted a powerful pull on our imaginations 鈥� not least through utopian science fiction. But in a world of autocracy, fanaticism and terrorism, it seems as far from reality as ever. Indeed, arguments still rage about his true intention. His title, derived from the ancient Greek ou-topos 鈥� meaning 鈥渘o place鈥� 鈥� is a pun on eu-topos, 鈥済ood place鈥�. Was More proposing a blueprint of an ideal society or satirising the self-interest, greed and military exploits of the hereditary monarchies of his time?

500 years of Utopia: The quest for the perfect society 鈥� and the lost civilisation that found it

The past, present and future of earthly paradises in history, books and art

On one thing nearly everyone agrees: no utopia has ever existed. Large human societies tend to be governed by coercion. The instinct for warfare has been a driving force in nearly every civilisation of the last five millennia, from ancient Mesopotamia to the British Empire.

Or has it? One mysterious, ancient society might give the lie to that. The civilisation of the Indus valley is the most enigmatic of the four great early civilisations. But while Mesopotamia, ancient Egypt and ancient China gloried in warfare, it seems absent from the Indus valley. Was this a real, functioning utopia? If so, how did it survive, and why did it eventually disappear?

The Indus civilisation flourished from about 2600 to 1900 BC. More than a thousand settlements have been found covering at least 800,000 square kilometres of what is now Pakistan, India and Afghanistan (see map), yet its remains were only discovered in the 1920s. It is now regarded as the beginning of Indian civilisation and possibly the origin of Hinduism.

鈥淚n a century of excavations, we have found just one depiction of fighting鈥�

All signs point to a prosperous and advanced society 鈥� one of history鈥檚 greatest. It had a vigorous maritime export trade via the Arabian Sea, and archaeologists have found objects made in the Indus valley in Mesopotamian cities such as Ur and Akkad. The two largest Indus cities, Harappa and Mohenjo-daro, boasted street planning and sewage worthy of modern times, including the world鈥檚 earliest known toilets and an impressive brick water tank known as the Great Bath.

Indus craftsmen created complex stone weights for commerce and long, precision-drilled carnelian beads for jewellery. Thousands of small sealstones have also been found; worn around the neck, merchants would have used them to stamp their identity on clay tags. Each one is carved with an exquisite but mysterious script, which has provoked more than a hundred published attempts to decipher its language 鈥� with little consensus.

Other aspects of the civilisation are even more perplexing. The chief cities show no clear signs of being fortified. No armour and no indisputably military weapon 鈥� as opposed to knives, spears and arrows designed for hunting animals 鈥� has been found. Nor is there evidence of the horse, an animal well suited to raiding parties, which later became common in the region. In nearly a century of excavations, archaeologists have uncovered just one depiction of humans fighting, and it is a partly mythical scene showing a female deity with the horns of a goat and the body of a tiger.

There is a total absence of conspicuous royal palaces and grand temples, no monumental depiction of kings and other rulers, not much difference between the homes of rich and poor, no sign of differing diets in the bones of buried skeletons and no evidence of slavery. All this stands in stark contrast with the ziggurats of Mesopotamia and pharaohs of ancient Egypt.

鈥淲hat鈥檚 left of these great Indus cities gives us no indication of a society engaged with, or threatened by, war,鈥� says Neil MacGregor, former director of the British Museum in London. The Indus people, he argues, offer a novel model of an urban civilisation, without celebration of violence or extreme concentration of individual power: 鈥淚s it going too far to see these Indus cities as an early, urban Utopia?鈥�

There are some who find a complete absence of war and conflict not credible. 鈥淭here has never been a society without conflict of greater or lesser scale,鈥� says Richard Meadow at Harvard University鈥檚 Peabody Museum. He argues that knives, spears and the like could have been used on humans as well as animals, and points out that the ancient Maya were once thought to be exceptionally peace-loving 鈥� until their hieroglyphs were deciphered, revealing stories of exceptionally bloody battles, sacrifice and torture. Who knows what the Indus script might reveal if it is deciphered?

Then again, even the Maya had fortifications around some of their cities and widespread depictions of warrior kings, so Meadow鈥檚 views are currently in the minority.

Most large societies lean on centralised governments to enforce the rule of law. Yet the only Indus sculpture that might conceivably depict a ruler is a small meditative bust of a bearded and cloaked man with partly closed eyes. Generally dubbed a 鈥減riest-king鈥� 鈥� because he wears a cloak over his left shoulder, much like Buddhist monks and Hindu priests, with a trefoil design that resembles one worn by Mesopotamian priests 鈥� his identity is in fact totally obscure.

Nonetheless, big engineering projects in the Indus valley would suggest some guiding authority existed to mobilise, direct and provision the workforce. Take the vast stone platforms that underlie various cities. They were built to raise buildings and streets above the level of the annual floods of the Indus river. Additional platforms were sometimes built on top, to further raise individual structures. At Mohenjo-daro, the foundational platform is 200 metres wide, 400 metres long and 5 metres tall. Indus excavator and scholar Gregory Possehl of the University of Pennsylvania calculated that it would have taken 10,000 men just over a year to build. This would have required some kind of central authority to mobilise and direct labourers. Of course, More made allowances for slavery in his Utopia, so perhaps this is just one more parallel between the fictional and real worlds.

Commercial networks spread over a vast area are another indication of a centralised authority. Lapis lazuli mined close to the trading post of Shortugai in what is now Afghanistan is found as far afield as Egypt. Goods were undoubtedly shipped via the Indus river and its tributaries, but many must have travelled overland. Such networks couldn鈥檛 have developed and operated for seven centuries without basic roads between settlements, presumably maintained by centrally directed taxation, plus some kind of regulatory framework to enforce the validity of long-distance commercial agreements.

And then there are the stone weights. They were standardised for commerce throughout the Indus valley and clearly worked well: the system survived long after the civilisation disappeared. Not only did it provide the weight standards for the earliest Indian coins, issued in the 7th century BC, the system is still used today for weighing small quantities in some traditional markets of both Pakistan and India.

鈥淲ho knows what the Indus script might reveal if it is deciphered?鈥�

It seems inconceivable that such a wealthy society could have survived for centuries without falling victim to aggressive invaders or embracing internal strongmen 鈥� Indus equivalents of Ramesses the Great in Egypt and Hammurabi in Babylon. How was this possible?

Part of the answer seems to have been geographical luck. The Indus civilisation had extensive lands ranging from river plains and coastlines to hills and mountains. Copious water flowed year-round down the Indus river and its four main tributaries, unlike the unreliable annual Nile inundation in Egypt. Raw materials were plentiful, including timber, semi-precious stones, and copper and other metals. And two growing seasons, arising from its winter cyclonic system and its summer monsoon system, would have provided abundant food. Egypt and Mesopotamia weren鈥檛 so lucky.

Eventual decline

As a result, the Indus peoples had no economic need to invade foreign lands, hence no need for militaristic leaders. As for invaders, who were the likely candidates? To the west, political and commercial relations were good, judging from the discovery of Indus settlements at Mehrgarh and Sutkagen-dor in neighbouring Balochistan. The same probably applied to Afghanistan to the north and north-west, on the basis of the settlement at Shortugai. To the east, in Rajasthan, there was only the inhospitable and sparsely populated Thar desert and the Aravalli mountain range.

Only in the south, on the Arabian Sea coast, might the Indus dwellers have faced attack. It鈥檚 perhaps no coincidence that this is where the only fortified settlements have been found. As for a possible attack from distant Mesopotamia, there would have been little motivation, given the value of the Indus trade, plus the fact that Mesopotamian rulers were preoccupied with internal battles.

So what eventually happened to the Indus civilisation? In the late 1920s, a group of 14 skeletons was unearthed in Mohenjo-daro, apparently caught in the act of fleeing the city. The discovery led to theories that migrants from Central Asia had attacked the Indus civilisation and initiated its decline: after flourishing for seven centuries, the peace-loving people met a violent end. But forensic study in the 1980s revealed that these victims died from malaria or other diseases, rather than massacre.

While major migrations from Central Asia between 1900 and 1500 BC are still thought to have played a role in the Indus鈥� endgame, changes to the environment may also have contributed. Climate change 鈥� an agent in the downfall of so many other civilisations 鈥� has been fingered: the archaeological record suggests the monsoon weakened around 2100 BC. And there are strong indications that the course of the Indus river and its tributaries shifted. A reconstruction of its course based on historical sources, past landforms and aerial photography shows major changes between 4000 and 2000 BC. The shift led to a growing flood threat to Mohenjo-daro, which could have caused the city鈥檚 eventual abandonment. All this could have been triggered by tectonic activity in the Himalayas: the region is prone to earthquakes; one damaged an Indus settlement at Dholavira in about 2200 BC.

It鈥檚 most likely that the decline of the Indus civilisation involved environmental and human factors operating in tandem. According to India鈥檚 leading Indus scholar, Iravatham Mahadevan, the very thing that made the Indus civilisation so special could have brought about its ruin. 鈥淭he civilisation seems to have declined and collapsed due to natural causes and also probably due to the failure of the ideology which bound the people together,鈥� he says. Possehl agrees. 鈥淭he Indus ideology ultimately had feet of clay,鈥� he writes in his book The Indus Civilization: A contemporary perspective. 鈥淚n the end their ideology made the Indus people who they were, but it may have proved to be their undoing as well.鈥�

In Possehl鈥檚 view, the lack of conflict and militarism endemic in the civilisation encouraged its original growth before 2600 BC and its relatively short flourishing, compared with Mesopotamia, Egypt and China. But it also accelerated the civilisation鈥檚 decline after 1900 BC. Indus egalitarianism and pacifism, though productive for a while, eventually led to stagnancy and inflexibility in the face of change.

There is, admittedly, limited evidence to confirm or deny Possehl鈥檚 hypothesis. It鈥檚 likely that we will remain in the dark until the tantalising Indus script is cracked. This should shed light on whether some degree of conflict, if not outright war, is vital to the survival of a civilisation 鈥� and whether Utopia really is 鈥渘o place鈥�.

This article appeared in print under the headline 鈥淔orgotten Utopia鈥�

AT GUGLIELMO MARCONI鈥檚 grand state funeral in Rome in 1937 鈥� orchestrated with military-style pomp by the black-shirted Benito Mussolini 鈥� the largest wreath on the hearse, adorned with a Nazi swastika, was sent by Adolf Hitler.

As the funeral began (6 pm precisely, Rome time, on 21 July), telegraph and radio stations in Italy, the UK, the US and Canada fell silent. As did the 31 beam and wireless stations of Cable and Wireless鈥檚 global network, and others in China, Japan, the Middle East and Europe.

Everyone knows that Marconi was the main pioneer of wireless communication. Yet we are far less confident about just which parts of this invention were his own work, in contrast with the inventions of near-contemporary, Thomas Edison. Now, at long last, we are offered a clearer picture in Marconi: The man who networked the world, a deeply researched and almost all-encompassing biography by Canadian media studies academic, Marc Raboy.

Fascinating and influential though Marconi was, the man who emerges does not inspire warmth, either in Raboy or, perhaps, in most readers of his notably balanced book. As Marconi remarked in 1934 in an exchange with the principal of the University of St Andrews, UK, after the students elected him lord rector: 鈥淗ave I done the world good, or have I added a menace?鈥�

Radio transmission is one of the great inventions of all time. But in Raboy鈥檚 view, 鈥淢arconi鈥檚 greatest invention was himself鈥�. Most of his massive biography is therefore devoted not to wireless science and technology per se but to its profound ramifications for national and international business and politics, and for the complicated identity of Marconi.

He was a man full of inner dissatisfaction, a womaniser with generally troubled personal relationships, including a failed marriage. Among men, Marconi 鈥渄idn鈥檛 really have friends, only associates鈥�, remarks Raboy. By contrast, 鈥淗e courted women who challenged him but married two who would never have dreamed of doing so.鈥� Raboy concludes: 鈥淪omething was missing鈥� perhaps a result of his mother鈥檚 unconditional devotion; he always, painfully, sought and was never able to find that in a companion.鈥�

A permanent outsider who longed to belong, Marconi was born in Italy in 1874 to an Italian Catholic father and an Irish Protestant mother, made his name and fortune in imperialist Britain at the turn of the century, and became a visiting celebrity in the US and Canada. He eventually returned to Italy to embrace Mussolini and Italian fascism, including the attack on what is now Ethiopia in 1935, when Marconi offered to serve in Africa. In his later years, he spent much time on the yacht he bought in 1919: a floating lab he named Elettra, after electrum: the Latin for amber, which creates a spark when rubbed.

鈥淔ascinating and influential though Marconi was, the man who emerges does not inspire warmth鈥�

In the mid-1920s, Marconi鈥檚 company started short-wave radio transmissions using the so-called Marconi beam system. These rapidly supplanted the cabled telegraphy introduced in 1830s, and led to the global connection we take for granted in our mobile telephony and the internet. The beam concept was Marconi鈥檚, but its key technology was an antenna designed by Charles Franklin, his employee, close colleague and collaborator, who went on to design the antenna for the first BBC television transmission in 1936.

After Marconi鈥檚 death, Franklin wrote of his boss with a mixture of respect and criticism: 鈥淗is scientific knowledge was weak, his engineering knowledge was weak, but he had a damned lot of intuition and common sense. He may have initiated the beam system but he didn鈥檛 know a thing about it.鈥�

Franklin鈥檚 analysis certainly applies to the most famous episode of Marconi鈥檚 tumultuous career. It was 1901 and Marconi was in Newfoundland, waiting for a signal to cross the Atlantic from a spark transmitter in Cornwall, UK.

At that time, physicists were convinced by the electromagnetic theory of James Clerk Maxwell and unaware of the existence of the reflecting ionosphere. They were sure that such long-distance atmospheric transmission was impossible because all electromagnetic waves travelled in straight lines, like light beams, and could not bend to follow Earth鈥檚 curvature. Marconi ignored conventional wisdom and ploughed on with his experiment. As Raboy writes, his 鈥渢inkerer鈥檚 experience鈥� made it happen by following hunch and intuition rather than scientific theory鈥�.

But, as with his later beam system, a crucial element in Marconi鈥檚 1901 equipment was not his invention: the sensitive detector known as a coherer. Originally conceived by French physicist Edouard Branly in 1890, Marconi鈥檚 1901 coherer was created by an Italian collaborator, Luigi Solari. He apparently based it on an unpatented mercury-based design by Indian physicist Jagadish Chandra Bose, published in the Proceedings of the Royal Society in 1899: a borrowing never acknowledged by the notoriously litigious Marconi and neglected, surprisingly, by Raboy.

Marconi鈥檚 very first coherer, undoubtedly based on Branly鈥檚, caused a sensation when he demonstrated it in public lectures by William Preece, the engineer-in-chief of Britain鈥檚 Post Office in 1896-1897. Concealed in a black box with an electric bell on top, the coherer could receive a signal from a spark transmitter that rang the bell, no matter where Marconi placed the black box, and without any visible connection between transmitter and box. There was immediate talk of 鈥渕agic鈥�, and comparisons with illusionist Harry Houdini. Even the University of Oxford called Marconi a 鈥渕agician鈥� in a speech conferring an honorary degree on him in 1904.

The coherer, now in the extensive Marconi collection at the Museum of the History of Science in Oxford, is reproduced in a new, superbly photographed guide to the museum. It is one of 35 intriguing objects taken from the museum鈥檚 collections, appealingly described by its director, Silke Ackermann.

These objects range from a metal astrolabe constructed by Muhammad Muqim al-Yazdi for Shah Abbas II of Persia in 1648 to a paper 鈥減hotogenic drawing鈥� John Herschel made in 1839 and a flask of penicillin culture made by one of its developers, Howard Florey, around 1940 鈥� plus a blackboard chalked by Albert Einstein in Oxford in 1931.

Marconi鈥檚 coherer certainly ranks with astrolabes, photography and penicillin. But as portrayed by Raboy, the man seems to me much closer in intellect and personality to, say, Steve Jobs than to Einstein. Despite Marconi鈥檚 limited original contribution to technology and science, we shall always owe him an enormous debt for his vision of universal communication.

This article appeared in print under the headline 鈥淭he Marconi connection鈥�

BIOGRAPHIES of Marie Curie tend to neglect her last two decades or so and concentrate on her scientific career up to the isolation of radium, for which she won her second Nobel prize in 1911. But, though scientifically less fruitful, her later years were in many ways the most eventful of her life.

In Marie Curie and Her Daughters, Shelley Emling focuses on this later era in the great scientist鈥檚 life. It included a controversial love affair with physicist Paul Langevin, a friendship with Albert Einstein, the establishment of the Radium Institute in Paris, her pioneering use of radiography on the French wounded in the first world war, her tours of the United States to raise money to obtain radium for her institutes in Paris and Warsaw, and her relationships with her daughters, scientist Ir猫ne Joliot-Curie and writer Eve Curie.

Science is not the strength of this book. Pierre Curie鈥檚 vital contribution and personality are rendered almost invisible, and Emling says little about the discovery of radioactivity by Henri Becquerel and the Curies in the 1890s 鈥� and botches the references she does make to the Curies鈥� legendary preparation of radium between 1899 and 1902.

Still, the book works well at a more personal level and inspires fresh admiration for Marie Curie鈥檚 dedication to science, ethics and individuals, particularly her two daughters. After working closely with her mother, Ir猫ne went on to win a Nobel prize for her work on artificial radioactivity in 1935, in collaboration with her own husband. Eve wrote a biography of her mother, Madame Curie, which was a worldwide bestseller in the 1930s and was adapted to make a Hollywood feature film in 1943.

Perhaps the most surprising part of the book, though, is to see how Curie鈥檚 welcome in the US in 1921 鈥� by universities, companies and public figures including US president Warren Harding 鈥� enabled her to shake off her dread of the spotlight. Wisely or not, Marie and Pierre always refused on principle to patent any of their techniques, and so their radium institutes were long deprived of resources. By her 1929 US tour, she used her fame to help raise funds for her institutes鈥� research.

Yet as this latest biography makes clear, it never went to her head. As Einstein once remarked, 鈥淢arie Curie is, of all celebrated beings, the only one whom fame has not corrupted.鈥�