The Art of Mendacity : MAKING THE MUMMIES DANCE: Inside the Metropolitan Museum of Art By Thomas Hoving , (Simon & Schuster: $25; 447 pp.)

In his 1981 book, “King of the Confessors,” Thomas Hoving placidly declared just how easy it had always been for him “to lie convincingly and without hesitation.”

A memoir written by an inveterate, acknowledged liar poses obvious complications for a reader. It’s even more daunting when the life under review has been influential in direct ratio to the scandals that have dogged it. How do you sift the truth from the mountain of fibs, or separate the facts from the self-serving whoppers?

Hoving is the brash art historian turned Parks and Recreation Department commissioner, who forsook New York City’s glamorous John V. Lindsay Administration in 1967 to assume the helm of the then dowdy Metropolitan Museum of Art. “Making the Mummies Dance” ostensibly chronicles his flamboyant, decade-long tenure as director of the 5th Avenue treasure house, where he melded his past experiences as politician, grandiloquent showman and pompous scholar in a radical reinvention of the museum profession.

In reality, this repulsive book is a case study of a man enchanted by petty power, and afflicted with an apparently pathological taste for falsehoods. Clumsily written, it’s gleeful in buffing up a stupendously disgraceful history. It’s also unintentionally useful. You may want to wash your hands after every chapter, but Hoving does show himself to have been a man of his time.

Politics always competed with the institutional world of art for Hoving’s affections, and his tenure at the Met coincided with Lyndon Johnson and Vietnam, Richard Nixon and Watergate. The scale of a museum director’s atrocities are of course far smaller than those perpetrated by Presidents, but the legacy can be much the same: a public institution deeply soiled by an enduring stain of suspicion and mistrust, enlarged through vile stratagems to keep the truth from ever being known. “Making the Mummies Dance” elaborates the cover-up.

New York had become the international center of the postwar art world, and because the Met was the city’s encyclopedic art museum, it inevitably became a model for countless others. Catching the updraft of the Swinging Sixties, Hoving ruffled the great, ponderous and decidedly snobbish institution. He expanded its size to Gargantuan proportions, ushered in a series of blockbuster shows, made controversial acquisitions, and swamped scholarship beneath a sludge of merchandising.

An inside view of this momentous transformation would be terrific. But you simply can’t trust what Hoving has to say, whether it’s about the uproar over the notoriously exploitative show “Harlem on My Mind” or about shady dealings in the million-dollar purchase of a rare, 6th-Century BC Greek vase, called the Euphronios krater.

The book is riddled with errors, such as the regular misidentification of artists and their work (Lucas Samaras mistaken for Walter De Maria; J.-L. David for Ingres; David Hare described as a painter, when his few paintings were an aberration in a prominent career as a sculptor; Verrocchio’s frescoes praised, when he painted none, etc.). More important, it depends on a phony device: Most everyone with whom Hoving came into contact, 15 to 25 years ago, is quoted verbatim.

Hoving declares that he relied on exhaustive written documents to reconstruct the past, including “direct quotes, conversations and discussions” dictated on tape at the time they occurred. When you plunge into his text, though, everyone who’s quoted happens to speak with exactly the same voice. Readers are set up in a game of bait-and-switch.

Repetitive, melodramatic and arch, Hoving’s voice isn’t hard to identify. It hums along relentlessly in the superlative mode. To wit: During a Mediterranean cruise on the private yacht of lavish Met patrons Charles and Jayne Wrightsman, our intrepid museum director examines sculptures that are “the most beautifully crafted I had ever seen,” after gazing out on “the greenest fields I had ever seen” and drinking “the crispest, driest, most frigid martini I had ever tasted.” All that in three short paragraphs.

The same hyperbole is brought to discussions of art. Hoving froths over Monet’s brisk painting of seaside strollers, “Terrasse a Sainte-Adresse,” and swoons in the face of Velazquez’s breathtaking portrait of “Juan de Pareja,” both of which he acquired for the museum. Yet, froth and swoon is all he does. In nearly 400 pages chronicling a decade at the helm of one of the most astounding art collections in the world, Hoving hasn’t a single insightful thing to say about any work of art.

Of course, art isn’t his top priority; polishing his place in museum history is. Here, the Kissingerian scale of the deceptions becomes gross.

Hoving doesn’t just lie. Frequently, he tells you about it. For his introduction to the “Harlem” catalogue, he invented an African-American family maid from his youth. In wooing Robert Lehman, he insisted he had visited Lehman’s collection, when in truth he had never seen it. For a benefactor who wanted a letter declaring a steeply inflated value for his past gifts of art, the Met director casually obliged.

Most egregiously, in the early 1970s Hoving disposed of two major paintings from the Met’s collection. Henri Rousseau’s “Tropics” and Vincent van Gogh’s “Olive Pickers” were quietly sold to a New York gallery in an effort to raise quick cash for other acquisitions. The self-proclaimed connoisseur tries to blame the sale on the bad advice of an underling, then earnestly insists he’s been absolved of any responsibility for the loathsome deed, because the attorney general of New York State could find no legal basis for an indictment. It’s the venerable “I am not a crook” defense.

The sales amounted to a consideration of the Met’s collection as principally a liquid asset--not the kind of posture that engenders confidence in potential donors of major art. But Hoving candidly recounts some taintings of the truth, which he happily told in the wake of the ensuing public furor.

The glibness of such candor concerning past prevarications has an insidious side: That Hoving honestly tells you when he’s lying encourages you to assume that, elsewhere, he’s telling the truth. But it’s no guarantee.

The shabbiest example concerns financier Robert Lehman, who had built a generally fine collection of European art. Hoving needed a coup to offset the growing scandals that threatened his job. So, in exchange for a gift of the collection, he agreed to house it as an entity independent from the rest of the museum, in a pavilion constructed to mimic rooms in Lehman’s Manhattan townhouse.

In effect, a private collector bought a home within a public institution. No director in his right mind locks a public trust into such a deal--the museum as condo--since it removes any flexibility from curatorial hands. The Lehman bequest set a horrific precedent.

The Lehman affair has likely done more lasting damage than anything in Hoving’s museum career. What does he have to say about it in “Making the Mummies Dance”? Now, he is casting himself as a forthright enemy of his own pavilion-in-perpetuity plan, one who only acquiesced because of meddlesome interference from incompetent Met trustees.

Here’s the kicker: Hoving relates a death-bed conversion on Lehman’s part. (No, I’m not kidding.) Lehman finally nods in dramatic consent to the director’s fervent plea “that after a period of 25 years his collections would be dispersed throughout the departments of the museum and the (Pavilion) turned over to special exhibitions. There is no doubt that Lehman knew what I was saying and agreed with me.”

If only the donor hadn’t died before he could change his will! Needless to say, there is no such provision in his Met bequest; the terms can be renegotiated after 35 years, but it doesn’t provide for dispersal.

Conveniently, the otherwise quote-loving author offers not a shred of corroborative testimony for his claim. Still, by the time he’s through--and Hoving repeats the bedtime story thrice in this squalid book--his hitherto unrevealed conversion of the donor has been magically transformed into “the original Lehman agreement.”

Without hesitation, as the lying King of the Confessors so gaily said--although not exactly convincing.