The National Geographic Society released the manuscript of what is called “The Gospel of Judas” yesterday. By National Geographic’s own account, a team first assembled by the Maecenas Foundation has been working on the text since 2001. As a result of press releases tied to publication of the text, widespread coverage has repeated the claim that this is an authentic and unique representation of the historical relationship between Jesus and Judas, and that Jesus encouraged Judas to betray him.

Despite the careful work by scholars that has gone into a document of obvious interest, I have to express disappointment when I see National Geographic stoop so low into hyperbole as to distort the significance of this discovery.

In its release, National Geographic repeatedly states that it has “authenticated” the document. Several press outlets have simply repeated those claims. But “authentic” turns out to be a slippery term as used by the National Geographic Society. No scholar associated with the find argues this is a first century document, or that it derives from Judas. The release says the document was “copied down in Coptic probably around A.D. 300,” although later that is changed to “let’s say around the year 400.” This amounts to saying that “The Gospel of Judas” is an authentic fabrication produced by a group of Gnostics in Egypt. Gnostics believed that their direct knowledge of heaven permitted them to understand what no one else knew, or could know by historical knowledge. For ancient Gnostics to believe in their own powers of divination is charming; for their flights of imagination to be passed off as historical knowledge in our time is dishonest or self-deceived.

During the second century, a theologian of the Catholic Church named Irenaeus referred to a writing named “The Gospel of Judas.” Was that a Greek version of the Coptic writing that National Geographic has just released? That question is not answered in the materials prepared for the press, because National Geographic never asks it. It just assumes the Coptic text is a direct translation from the Greek, so it can knock another century or so off its apparent age, and claim its text as a second-century writing.

The fact is that we do not know the relationship between what Irenaeus referred to and the Coptic “Gospel of Judas,” nor how that involves (if at all) a document of the same name that another teacher, Epiphanius, referred to two centuries later. As a matter of fact, Epiphanius’s description of the contents of “The Gospel of Judas” seems closer to National Geographic’s manuscript than what Irenaeus said, because Irenaeus refers to a more mythologically elaborate teaching, involving Judas with Cain, Esau, Korah, and the Sodomites.

After being discovered in Egypt in the 1970s, National Geographic’s manuscript was badly damaged, perhaps as a result of repeated attempts by earlier owners to sell it (sometimes at a high price, which it never fetched). As late as last February, National Geographic reports, “a missing half-page of the gospel resurfaced in New York City.” This does not inspire confidence in the chain of custody or the document itself. The whole episode is an example of the damage to knowledge caused when people take documents, try to sell them, and then others resort to sensation to sell, if not the physical remains, then their own findings.

Yet Terry Garcia of National Geographic actually states in the release that the document “has been authenticated as a genuine work of ancient Christian apocryphal literature”; in other words, that it is an authentic forgery. Mr. Garcia is identified in the release as “executive vice president for Mission Programs for the National Geographic Society” – a Gnostic missionary, we are left to gather.

Not content with vapid claims of authenticity, National Geographic goes on to claim that “The Gospel of Judas” gives “new insights into the disciple who betrayed Jesus.” It does not. In this Gospel, Judas is supposed to act with Jesus’s advice and encouragement. That is precisely what is portrayed in the New Testament, especially in John 13:21-30. So convinced were they that their find is better than the Gospels in the New Testament, the authors of the release did not bother to read the New Testament.

But let’s forget the hyped assertions of the significance of this text, and just concentrate on what National Geographic tells us about “The Gospel of Judas” as a Gnostic document. The release only consults one expert about the handwriting of the document, Stephen Emmel, and his comments contradict one another by a century. Does he believe this document was written in 300 or in 400? There is a difference, and my own impression (from the photographs, which have circulated on the World Wide Web for some months) is that we are dealing with a later hand. In any case, paleographers do not normally deal in general impressions but compare characters from documents of unknown dates to documents of known dates. Acknowledged experts in this field who have concentrated on “The Gospel of Judas,” including James Robinson and Charles Hedrick, were not consulted for some reason. Did National Geographic want to keep some scholars of Coptic away from this document?

That is a waste of a unique finding; “The Gospel of Judas” offers rich insights into ancient Gnosticism, particularly into the way in which Gnostics saw Jewish institutions transformed by Jesus. (The discourse on the Temple is especially significant, and involves the unusual view among Gnostics that Jesus’s death was a necessary sacrifice.) But that is likely to be obscured by silly claims that the “real” Judas is at issue in this document.

Mr. Chilton’s most recent book, “Mary Magdalene: A Biography,” is available from Doubleday.