This is the story of Atrahasis (the Supersage), and Finkel's book discusses these two flood accounts and their relationship to the Bible. He talks of itinerant bards wandering from village to village, entertaining their listeners with well-rehearsed details in return for a "mess of pottage", almost as if he had sat at their knees. But the greatest storyteller of all is Finkel himself, who enchants us with a linguistic link between the flood and the survival of a baby set adrift in a basket on a river. This was Sargon the Great of Akkad, who lived a thousand years before Moses.

But back to the tablet. As he tells us, its first line, "Wall, wall! Reed wall, reed wall!" confirms it immediately as a flood story. This is the god Enki/Ea speaking to the reed wall, intending Atrahasis to hear and grasp his warning before the great god Enlil unleashes a mighty flood on the human race. And although this brief tablet continues, "Atrahasis, heed my advice, that you may live forever," it is not so much a literary text as an extremely detailed account of what was needed to build the Ark. But what was its purpose, and how does it fit in with previously known accounts?

In coming to his conclusions, Finkel gives a masterful account of how the main languages of Mesopotamia — Sumerian and Akkadian — were written in cuneiform on clay tablets. The great flexibility of the script leads to ambiguities on how to interpret individual signs, to say nothing of chipped and broken tablets, but Finkel is quite clear that the new tablet showed the shape of the Ark to be circular.

The word for circle appeared in another flood account, but was interpreted as "area" because a circular Ark seemed an anomaly. It was not the cube suggested in Gilgamesh, nor the oblong boat of another account that got transmitted into the Bible, yet in the rivers of Iraq, north of the marshes, round coracles were used extensively, and for a floating lifeboat such a design was ideal. The sides of the boat are made of rope, coiled around in multiple layers, and sealed with bitumen.

The detailed numerical data show a rope that could stretch from London to Edinburgh, but it all fits with the amount of bitumen, the height of the sides and the area of the base. Could this be a copy of some original instructions? The tablet even talks of the animals entering two by two. And in case you want to quibble about seven pairs of clean animals in the Bible, Finkel analyses that in terms of two different authors, known as J and P in biblical exegesis. He assembles the pieces of a marvellous jigsaw puzzle, drawing intriguing links between different flood accounts and their transmission to the Bible.

While reading this fascinating material, I learned that the new tablet has exactly 60 lines, and my interest was piqued. Sixty was the base for all Babylonian mathematics — and is the reason we have 60 seconds in a minute, and 60 minutes in an hour — so might this tablet be connected with some mathematical study? As you read the book it seems as if the real purpose of the tablet will never be revealed, but worry not — Irving Finkel is a superb storyteller, taking the reader on a journey not to be missed.