Land of Marvels, By Barry Unsworth

For the best part of three decades, Barry Unsworth has excelled at the kind of period novel that not only makes history live again but confirmss the truth of William Faulkner's dictum: "The past is never dead. It's not even past." In 2006, with Islam's historic position in Europe a question that bred far more heat than light, he made a typically deft detour into – of all locations – 12th-century Sicily. There, The Ruby in Her Navel unfolded as a thrilling and colourful romance that hunted with great cunning and finesse for the roots of the inter-cultural amities, and enmities, that shape our lives.

Its successor novel takes place in spring 1914, near a tributary of the Euphrates in the Ottoman province of Mesopotamia. The word "Iraq" appears once, to finish the book's final sentence. Unsworth does not trade in hindsight or allegory. His technique treats history not as a mirror of the present, nor as a dressing-up box where modern-minded folk put on fancy dress. Rather, the past exists as a kind of palimpsest: a manuscript with stories rubbed out and reinscribed, but with older versions always legible beneath. How fitting, then, that his 16th novel should be about a bunch of archaeologists.

In early 1914, with the chancelleries of Europe buzzing with talk of war, the desert digs of Mesopotamia set scholar against scholar in "a microcosm of our divided world". Meanwhile, great-power agents, keen to prey on Turkish weakness, snoop around the sands.

In one corner of this circus of rival intellects and states, where the enfeebled Ottomans can keep watch on intruders but seldom intervene, the amateur excavator Somerville is desperate for a sensational find. Short of cash, treated with scorn by his hero-fancying wife Edith, he yearns to prove that his unpromising mound of earth harbours something big in late-Assyrian history before a German-funded railway line smashes through on its destabilising way towards the Gulf.

High-minded but short-sighted, Somerville and his more pragmatic sidekick Palmer (with his Suffragist sweetheart Patricia in tow) do delve, layer by layer, towards a momentous discovery about the last days of a once-rapacious empire. Like all empires, the Assyrians "gloried in dominion", cultivated death-defying fantasies and never felt "the touch of mortality" – as shrewd Patricia notes. Other visitors to the site at Tell Erdek have their own dreams to dig. Somerville's Arab informant Jehar craves the cash to make his reverie of married life with the Circassian beauty Ninanna – in thrall to a fairy-tale wicked uncle – come true.

Major Manning, "a perfect type of British army officer", blusters around the desert on secret imperial business. And the rangy American geologist Elliott – seductive servant of many masters – pretends to be an archaeologist while nosing out the region's underground lakes of oil. This new black gold, recently chosen by Winston Churchill as the Royal Navy's future fuel, will carry in on its gushing tide a new "golden age" of properity. Oil, we grasp, will "change the face of the planet". In London, Constantinople and Damascus, the fleshy entrepreneur Lord Rampling surveys the grand strategic picture beyond these desert tracks and streams. Cynical but peaceable, he smells the oil in its world-changing reservoirs, and hopes that, as usual, money will "work in silence to make partners of enemies". A fruity Edwardian intriguer out of Shaw, Rampling believes that diplomatic gambits can press to the extreme edge of the rules because the lure of profit will always trump the risk of war. As did his caste, from the Thames to the Golden Horn, throughout that fateful spring.

Unsworth's swift and sure touch as narrator means that each side of the story bounds along. We get to know Major Manning's plans for the charming, triple-dealing Elliott – and vice versa. As the fuel-seeking hound from the far West charms his wife, Somerville excavates his way towards a revelation about an empire's downfall. With the hard-won ease of a long-polished craft, Unsworth can make the details of petroleum geology and late-period Assyriology as engaging as – say – Elliott and Edith's nocturnal ride to watch fire-worshippers gathered at the flame from a leak of rock-bound gas. Undertones of doom never silence the high notes of an elegantly-dressed adventure yarn. Far from the oil deposits and sleeping tombs, Rampling grasps that the old European game of cheat, bluff and carve-up-the-spoils may soon end in floods of tears as well as oil.

The plot, so delicately stitched, unravels – literally – in a flash. A miscalculation by a minor player, acting unawares within a vast, unstable tinderbox, reduces many of these stories to an abrupt terminus. This distant catastrophe, we learn, added to Europe's "general feeling of apocalypse" during the summer of 1914. As always with Unsworth, no moral lectures or glib ironies ensue. Rather, we glimpse what happened to these folk (or those who survived) during and beyond the first global war. It ended with, among many other new-born nations, the Anglo-French fabrication of the four-letter land whose name ends this compelling – and unsettling – book.