ON Friday, NBC will air a special commemorating the 25th anniversary of the landmark miniseries based on Alex Haley’s book “Roots.” Ironically, the original series aired on ABC – but officials at that network took a pass on broadcasting the tribute.

What’s truly amazing, however, is that “Roots” is receiving a reverential tribute at all. For while the miniseries was a remarkable – and important – piece of television, the book on which it was based has now been widely exposed as a historical hoax.

Unfortunately, the general public is largely unaware of how Haley’s monumental family autobiography, stretching back to 18th-century Africa, has been discredited.

Indeed, a 1997 BBC documentary expose of Haley’s work has been banned by U.S. television networks – especially PBS, which would normally welcome such a program.

Coincidentally, the “Roots” anniversary comes amid the growing scandal over disclosures of historian Stephen Ambrose’s multiple incidents of plagiarism. Because as Haley himself was forced to acknowledge, a large section of his book – including the plot, main character and scores of whole passages – was lifted from “The African,” a 1967 novel by white author Hal Courlander.

But plagiarism is the least of the problems in “Roots.” And they would likely have remained largely unknown, had journalist Philip Nobile not undertaken a remarkable study of Haley’s private papers shortly before they were auctioned off.

The result was featured in a devastating 1993 cover piece in the Village Voice. It confirmed – from Haley’s own notes – earlier claims that the alleged history of the book was a near-total invention.

“Virtually every genealogical claim in Haley’s story was false,” Nobile has written. None of Haley’s early writing contains any reference to his mythic ancestor, “the African” named Kunta Kinte. Indeed, Haley’s later notes give his family name as “Kante,” not “Kinte.”

And a long-suppressed tape of the famous session in which Haley “found” Kunta Kinte through the recitation of an African “griot” proves that, as BBC producer James Kent noted, “the villagers [were] threatened by members of Haley’s party. These turn out to be senior government officials desperate to ensure that things go smoothly.”

Haley, added Kent, “specifically asks for a story that will fit his predetermined American narrative.”

Historical experts who checked Haley’s genealogical research discovered that, as one put it, “Haley got everything wrong in his pre-Civil War lineage and none of his plantation ancestors existed; 182 pages have no basis in fact.”

Given this damning evidence, you’d think Haley’s halo would long ago have vanished. But – given this week’s TV tribute – he remains a literary icon. Publicly, at least.

The judge who presided over Haley’s plagiarism case admitted that “I did not want to destroy him” and so allowed him to settle quietly – even though, he acknowledged, Haley had repeatedly perjured himself in court.

The Pulitzer Prize board has refused to reconsider Haley’s prize, awarded in 1977 – in what former Columbia President William McGill, then a board member, has acknowledged was an example of “inverse racism” by a bunch of white liberals “embarrassed by our makeup.”

Yet the uniqueness of “Roots” is that it was presented as factual history, albeit with fictional embellishments. Haley himself stressed that the details came from his family’s oral history and had been corroborated by outside documents.

But Professor Henry Louis Gates of Harvard, a Haley friend, concedes that it’s time to “speak candidly,” adding that “most of us feel it’s highly unlikely that Alex actually found the village from whence his ancestors sprang.”

Yet even today, much of America – both black and white – continues to perpetuate the “Roots” myth.

In 1997, Haley’s older brother George was named U.S. ambassador to the Gambia – his family’s supposed homeland. Then-Vice President Al Gore said at the time, “George Haley is the direct descendant of Kunta Kinte.” Added Gore: Haley’s appointment would “complete a cycle of history.”

Haley’s defenders insist that the literal truth of “Roots” is less important than its larger truth; that, as Gates has put it, ” ‘Roots’ is a work of the imagination” that was “an important event because it captured everyone’s imagination.”

True, Haley’s literary fraud doesn’t alter the historical reality of slavery and its evils, or the pernicious lasting effect it had on America. But there’s a pernicious paternalism at work when it’s suggested that an ostensible work of history shouldn’t be held to account merely because its heart is in the right place.

Haley himself later admitted he was “caught up in the sweep and the swell of the overall thing,” saying that “the quest for a symbolic history of a people just swept me like a twig atop a rushing water.”

Maybe. But as the late John Henrik Clarke, dean of Afrocentrist scholars – who admitted that he “cried real tears when I realized that Haley was less than authentic” – argued: “We don’t need no more fakers. We don’t need no more phonies. We can take our tea with or without sugar.”