This ancient collection of 70 tiny books, their lead pages bound with wire, could unlock some of the secrets of the earliest days of Christianity.
Academics are divided as to their authenticity but say that if verified, they could prove as pivotal as the discovery of the Dead Sea Scrolls in 1947.
On pages not much bigger than a credit card, are images, symbols and words that appear to refer to the Messiah and, possibly even, to the Crucifixion and Resurrection.
Adding to the intrigue, many of the books are sealed, prompting academics to speculate they are actually the lost collection of codices mentioned in the Bible's Book Of Revelation.
The books were discovered five years ago in a cave in a remote part of Jordan to which Christian refugees are known to have fled after the fall of Jerusalem in 70AD. Important documents from the same period have previously been found there.
Initial metallurgical tests indicate that some of the books could date from the first century AD.
This estimate is based on the form of corrosion which has taken place, which experts believe would be impossible to achieve artificially.
If the dating is verified, the books would be among the earliest Christian documents, predating the writings of St Paul.
The prospect that they could contain contemporary accounts of the final years of Jesus's life has excited scholars - although their enthusiasm is tempered by the fact that experts have previously been fooled by sophisticated fakes.
David Elkington, a British scholar of ancient religious history and archeology, and one of the few to have examined the books, says they could be 'the major discovery of Christian history'.
'It is a breathtaking thought that we have held these objects that might have been held by the early saints of the Church,' he said.
But the mysteries between their ancient pages are not the books' only riddle. Today, their whereabouts are also something of a mystery. After their discovery by a Jordanian Bedouin, the hoard was subsequently acquired by an Israeli Bedouin, who is said to have illegally smuggled them across the border into Israel, where they remain.
However, the Jordanian Government is now working at the highest levels to repatriate and safeguard the collection. Philip Davies, emeritus professor of biblical studies at Sheffield University, said there was powerful evidence that the books have a Christian origin in plates cast into a picture map of the holy city of Jerusalem.
'As soon as I saw that, I was dumbstruck,' he said. 'That struck me as so obviously a Christian image. There is a cross in the foreground, and behind it is what has to be the tomb [of Jesus], a small building with an opening, and behind that the walls of the city.
'There are walls depicted on other pages of these books too and they almost certainly refer to Jerusalem. It is a Christian crucifixion taking place outside the city walls.'
The British team leading the work on the discovery fears that the present Israeli 'keeper' may be looking to sell some of the books on to the black market, or worse - destroy them.
But the man who holds the books denies the charge and claims they have been in his family for 100 years.
Comment: They've been in his family for 100 years... yet they were discovered in a cave 5 years ago?
Dr Margaret Barker, a former president of the Society for Old Testament Study, said: 'The Book of Revelation tells of a sealed book that was opened only by the Messiah.
'Other texts from the period tell of sealed books of wisdom and of a secret tradition passed on by Jesus to his closest disciples. That is the context for this discovery.'
Professor Davies said: 'The possibility of a Hebrew-Christian origin is certainly suggested by the imagery and, if so, these codices are likely to bring dramatic new light to our understanding of a very significant but so far little understood period of history.'
Mr Elkington, who is leading British efforts to have the books returned to Jordan, said: 'It is vital that the collection can be recovered intact and secured in the best possible circumstances, both for the benefit of its owners and for a potentially fascinated international audience.'
*British scientists have uncovered up to eight million mummified dogs, thought to have been sacrificed to Anubis, the god of the dead, 2500 years ago after excavating tunnels in the ancient Eygptian city of Saqqara.