It reads like a sequel to Raiders of the Lost Ark. An ambitious young museum curator is on the trail of the legendary "King of the Confessors," a two-foot-high ivory cross, missing for eight centuries. Along the way, the hero of our story bargains with a shady Yugoslav collector, breaks into a glass case in a Florence museum with his Swiss Army knife and colludes with a smuggler to have another treasure, an 800-year-old Romanesque stone relief, whisked out of Italy.

Yet these are not the further adventures of Indiana Jones, but rather the story of Thomas Hoving, director of New York's Metropolitan Museum of Art from 1967 to 1977. Writing in the heady prose of a thriller, Hoving, 50, relates his escapades in the just-released King of the Confessors (Simon and Schuster, $16.95). Even before it hit the bookstores, Confessors was being greeted with outrage and scorn from the art establishment and charges that Hoving played fast and loose with the facts to make his narrative more exciting. "The only thing you can believe for sure," quipped William Wixom, chairman of the Medieval Department and the Cloisters (the Metropolitan's uptown branch), "is that Tom has no difficulty in lying." Hoving does admit to literary license on the Swiss Army knife caper. "Look," he says, "I was able to get the ivory out of the case without authorization," but he refuses to tell just how.

He is not as discreet about his colleagues' foibles. In fact, he insults his former friend and mentor, the late James Rorimer, who was the Met's director for 11 years, depicting him as pompous, jealous, conniving and vacillating to the point where the museum almost lost the fabled cross. "For some reason," comments an official at the Metropolitan, "Tom Hoving has chosen to take an interesting subject and make it into a cheap, distorted and spiteful book."

No matter that it is fanciful and self-aggrandizing, Confessors is a rousing detective story that plays up the seamier side of acquiring art works. Hoving describes himself as a J.R. Ewing of the art world. "Within a month of starting at the Metropolitan [as a 24-year-old curatorial assistant in 1955]," he writes, "I had charted my goals. I would become curator of the Medieval Department and the Cloisters. I would become director of the museum. I recognized I had winning, if not particularly winsome, assets. I knew I could be quick, disciplined, tough, sensitive and ruthless. I could be devious without qualms."

Hoving called on all these qualities in his quest for the "incomparable" medieval cross, which he first heard about in 1960. He details his Byzantine negotiations with the improbably named Yugoslav collector, Ante Topic Mimara, his competition with the British Museum and his eventual success in persuading the Metropolitan to part with $600,000 to buy the cross in 1963. "It was chase and capture," beams Hoving. "One of the most invigorating endeavors in life." The cross is now on permanent exhibit at the Cloisters.

"Confessors is too dull to be a novel and too frivolous for a serious book," sniffs Carmen Gomez-Moreno, the current curator of medieval art at the museum. In turn, Hoving is irritated by the museum's reaction. "I think it is rather bush league of the Metropolitan to jump up and down and issue cute statements," declares Hoving. "They are flaring their nostrils for a very mundane reason. They are negotiating with the Italian government over a loan show right now and are annoyed that all this [the 1960 smuggling of the stone relief] should be revealed. I told them to say to the Italians, 'Hoving doesn't work here anymore,' which happens to be true."

Indeed, since Hoving resigned his $75,000-a-year post at the museum he has written two other books, appeared regularly on ABC's 20/20, and last month became editor in chief of Connoisseur magazine. According to the New York-born Hoving, Confessors is just the first in a planned trilogy. "The first book reveals my brash, risk-taking, stupid youth," he maintains. "The next deals with my joy, triumph and total lack of anxiety, and the third will be—I don't know—something else." The second installment, already under way, may cast further doubt on the veracity of the current volume. The title of book two: This Alone Is Truth.