The Indus civilisation—which inspires R. Balakrishnan and his groundbreaking book—flourished from circa 2500 to circa 1800 bc. Centred in the valley of the Indus River, it covered a total area in today's Pakistan and India about twice that of its contemporaneous civilisations in Egypt and Mesopotamia. Since its discovery by British and Indian archaeologists a century ago, announced with a fanfare in 1924 by their leader John Marshall in the Illustrated London News, it has become a byword for mystery and a source of endless speculation. Unfortunately, discoveries of well over a thousand Indus settlements since the 1920s up to the present day have intensified, rather than resolved the mystery.

Was the civilisation indigenous in origin or influenced by neighbouring Mesopotamian civilisation, which certainly predates it? Why do its towns and cities—most famously Harappa and Mohenjo-daro—have technologically advanced brick buildings and hydraulic systems such as wells and drains, but no identifiable palaces or temples? How was it ruled, given that it shows no reliable evidence of kings, priests, or warriors, yet extensive evidence of long-distance trade, including maritime trade via the Arabian Sea with Mesopotamia (where Indus-created objects have been discovered)? Why are its sophisticated arts and crafts, such as finely drilled carnelian jewellery, always expressed on a miniature scale—unlike those of Egypt and Mesopotamia? Was its religion the origin of Hinduism, as suggested by certain Indus objects, despite zero evidence of a caste system? What caused its eventual disappearance: migration of strangers from the west, internal political collapse, earthquakes, changes in the course of the Indus, climate change, or some combination of these?

Above all, perhaps, what is the meaning of the exquisitely carved Indus script? In appearance this resembles no other writing system. Nevertheless, scholars and others have sought to link the Indus script with numerous far-flung places and have offered more than a hundred published decipherments since the 1920s, most of which differ radically—making it the most deciphered script in the world.

To quote Asko Parpola, the leading Indus script scholar, in his classic 1994 study, Deciphering the Indus Script:

Parpola himself—while offering only some generally cautious readings of certain Indus inscriptions—favours a linguistic and cultural link between the Indus civilisation and the Dravidian civilisation of South India, as described in the Tamil literature of the Sangam period (dating from perhaps 600 bc to circa ad 300), which contains numerous references to earlier texts and poems and also to geographical features, such as the Himalayas, far from today's Tamil country. This Dravidian hypothesis is passionately endorsed by Balakrishnan, a postgraduate in Tamil literature. It energizes his massive, magnificently produced, and copiously illustrated study. ‘The mystery that surrounds the origins of Tamil matches the mystery that surrounds the eclipse of the Indus civilization,’ he writes (p. xii). Hence his book's title, Journey of a Civilization, and its subtitle, Indus to Vaigai, referring to two rivers, the second of which flows through Tamil Nadu state from the Western Ghats into the Palk Strait between Tamil Nadu and Sri Lanka.

Indeed, Balakrishnan often refers respectfully to the work of Parpola and, even more frequently, to that of another distinguished Indus script scholar, hailing from Tamil Nadu, the late Iravatham Mahadevan, who first inspired Balakrishnan's study of the Indus civilisation in the 1980s. He dedicates his book to Mahadevan, ‘my teacher’. All the more surprising, then, is that the book sometimes omits vital source references, and contains no footnotes, without any explanation of these omissions from the author.

Its investigation of the Indus-Dravidian connection is extremely complex and inevitably highly speculative. So much so that Balakrishnan's methodology is worth quoting at some length, as set out in his Introduction in nine brief summaries:

1. 1. ‘To identify, based on the archaeological evidence and the “visuals” of Indus seals, certain fundamental characteristic features of the civilization; to a greater extent this task has been handled by several scholars.’

2. 2. ‘To advance the view that migrations are an integral part of prehistory and migration-related studies will be of great help in reconstructing the post-Indus past.’

3. 3. ‘To probe the post-Indus cultures and early Indian literature to compare, match and contrast with what can be considered as unique or prominent Indus ideologies and argue how the basic structures of Indus ideology have a greater traceability in the Dravidian context.’

4. 4. ‘To find evidence to argue that the spatio-temporal distances assumed between the Indus civilization and Dravidian south do not matter. Focused archaeological efforts, research on ancient Tamil texts, epigraphy will bridge that gap.’

5. 5. ‘To map the territories and locations referred to in Sangam texts and prove the point that the geography of the Sangam texts was not coterminous with the political boundaries of the Sangam Age and link the “flashbacks” and “carried forward” landscapes to post-Indus migrations and recalled past.’

6. 6. ‘To use onomastics as a major tool to trace the journey of this civilization from the Indus to the Vaigai-Tamiraparani region and place them in consonance with Indus-Old Tamil legacies and the emerging new archaeological clues.’

7. 7. ‘To interpret the “public memories” prevalent among various communities about their “collective past” and locate onomastic pathways to reconstruct past migrations including directions.’

8. 8. ‘To trace the continuity of Indus cultural practices such as bull vaulting and cockfight and assess their historical and contemporary relevance in different language-speaking cultures.’

9. 9. ‘To map the lexical encoding processes of certain key terminologies that represent some overarching ideologies of the Indus civilization like salience of the colour red, the importance of pottery and bronze, and cardinal directional terms.’

Onomastic analysis provides probably the most substantial evidence in the book, as suggested in the chapter entitled ‘Place-names do travel: onomastic footprints’. One of its intriguing maps shows European and African place-names in the United States, such as London in Ohio and Cairo in Georgia. Balakrishnan decided to search for similarities in place-names between northwestern India and ancient Tamil place-names attested in the Sangam texts, using a GIS (geographic information system). He located the crucial Tamil place-names Korkai, Vanji, and Tondi, and many other prominent place-names in northwestern India, and eventually announced in 2010 the existence of the Korkai-Vanji-Tondi Complex as evidence in support of the Dravidian hypothesis. Another interesting linguistic parallel is the word kot—frequently used as a suffix to designate ‘fort’ in the northwest—and the word kottai—a place-name suffix also meaning ‘fort’, common in Tamil Nadu.

The colour red is another suggestive parallel. In the Indus civilisation, red brick, red pottery, and carnelian jewellery are important. There are also traces of red paint on many Indus objects, ranging from the famous ‘priest-king’ statuette to a small elephant-head sculpture and also baby rattles. In Tamil Nadu, a key deity is Murugan, also known as the ‘Red God’ because of his red complexion, garments, and decorations. Red is also emphasized in the Sangam literature.

But many Indus-Tamil links discussed by Balakrishnan are much more speculative. An example is bull sport: jallikattu is an ancient Tamil custom of bull-embracing, still controversially celebrated today, in which a bull is released into a crowd and one-by-one as many people as possible jump upon it and try to hold its hump while the bull attempts to escape. Two dramatic Indus seals depict what might be a comparable, much earlier custom: they show what appear to be human bodies gyrating wildly in the air above an agitated buffalo or bull. Yet, notes Balakrishnan, Ernest Mackay, a key Indus scholar in the 1930s, could not make up his mind whether this Indus seal image depicted an attack on humans by a wild bull or rather humans disporting themselves with a trained bull, as in the ancient Minoan custom of bull-leaping. Moreover, a direct link between the Indus civilisation and the sport jallikattu is surely debatable, because jallikattu does not involve humans aiming to leap over the bull, Minoan-style, as shown in the two Indus seals. Nor is there any further evidence of bull sport in the Indus civilisation.

Then there are the potsherds recently discovered at Keeladi, a Sangam-age settlement on the Vaigai. Inscribed in the Tamil-Brahmi script, they also have graffiti marks that remind some Indian scholars of Indus script signs. Five of these marks are charted by Balakrishnan next to five supposedly comparable Indus signs. But the resemblance is far from convincing, even to the trained eye. As Parpola informed me recently: ‘I do not take seriously the supposed resemblance between the Keeladi graffiti and some signs of the Indus script.’ Balakrishnan would like to see a resemblance but honestly admits: ‘The future decipherment of both the graffiti and the Indus script alone could solve the issue’ (p. 459).

As always with the Indus civilisation, we need more—and more reliable—evidence. Meanwhile it continues to fascinate the world. Journey of a Civilization will further fuel this fascination, while at the same time demonstrating the power of a hypothesis to both clarify and complicate ancient historical interpretation.