IN THE LAST 20 years, the market for works of art has

risen so meteorically that million-dollar paintings are almost commonplace. Concurrently, of course, art theft has become a growth industry which now stands second only to illegal drugs on the roster of international crimes. "If you want to see Italy--hurry!" This black joke is uncomfortably close to the truth. Twelve thousand works of art are stolen annually from that country alone.

Seymour Reit's fascinating account of the theft of the Mona Lisa from the Louvre takes us back to a more innocent time. The extraordinary feat of extracting the most famous work of art in the world from the most formidable museum was accomplished with insolent ease. On August 19, 1911, an itinerant Italian carpenter named Vincenzo Perugia simply lifted the masterpiece from the four hooks which supported it in the Salon Carr,e and walked off with it. It was a Monday, the museum was closed, and Perugia was wearing a workman's tunic. Paintings were often carried off to be photographed, and no one noticed him. He removed La Gioconda from her frame, stuck the panel under his tunic, and ambled out the Porte Visconti. No one even noticed the theft until the next day.

Reit's account of the frenzied search for the missing picture--including the brief incarceration of Pablo Picasso and his friend, the poet Guillaume Apollinaire--is a hilarious comedy of errors. Amazingly, the painting did not surface for two years. In December, 1913, Perugia contacted a Florentine art dealer named Alfredo Geri, who in turn contacted the police. At his trial, Perugia claimed a high-minded motive for the theft. Enraged by the Napoleonic plunder of Italy's treasures, Perugia stated that he merely wished to restore part of Italy's artistic patrimony. (The 500,000 lire he had demanded from Geri were, apparently, to be viewed as a reward for his patriotism.) Not surprisingly, Perugia was hailed as a national hero and the penalty handed down by the Italian judges was nominal.

According to Reit, however, Perugia was only a pawn, and the theft of the Mona Lisa only a subplot. Reit has unearthed a certain "Marqu,es de Valfierno" who allegedly masterminded a complex scheme. Following Valfierno's later admission (or intervention), the theft of the panel merely set the stage for the real crime: the sale of six fake "Mona Lisas" to gullible millionaires. For this purpose Valfierno supposedly employed a master forger, one "Yves Chaudron."

Unfortunately, both Valfierno and Chaudron remain rather too elusive and shadowy to be quite convincing. If Chaudron accomplished what Reit claims, he must have been the greatest faker of all time. For, in a few months he completed six identical replicas of a work that took Leonardo da Vinci a number of years to paint. And if Chaudron did, where are they now?

Reit is also on thin ice when, at the end of the book, he uncovers a version of the picture in a New Jersey bank vault which he claims to be Leonardo's first Mona Lisa. There are two autograph versions of the Madonna of the Rocks, Reit argues, so why not two Mona Lisas? The answer to this question can be found among the illustrations, where the murky shadows and smirky expression of the New Jersey painting may be compared to the original.

The legends surrounding Leonardo's great portrait are already so rich and colorful that Reit can hardly be faulted for adding to the mythology. The Day They Stole the Mona Lisa is highly entertaining, and a little skepticism does not detract from the reader's pleasure.

Rogues in the Gallery, by Hugh McLeave, induces no skepticism at all. Drawing on sources such as Interpol, the French Suret,e and Scotland Yard, McLeave's study presents a solidly documented overview of art theft illustrated with a number of fascinating cases.

An art crime is a complex affair. A grave robber is inexorably linked to a middleman, and ultimately to the greedy collector or curator who knowingly buys stolen or smuggled goods. By clarifying this chain of complicity, McLeave suggests ways in which the current epidemic of art thefts may be combatted.

McLeave's book has both heroes and villains. Rodolpho Siviero, the head of Italy's art recovery office, is one of the great heroes. As a result of his efforts, thousands of works looted by the Nazis have been restored to Italy. In the line of duty, Siviero has had to confront thugs, crooked dealers and curators, and even governments-- including, at times, his own. On top of the legal and political dangers of his job are the physical ones: in one hair-raising episode, McLeave records how Siviero's recovery of a famous Greek sculpture landed him in the basement of an antique store near Rome, surrounded by armed Mafiosi.

Another of McLeave's heroes, the pseudonymous "Henri Collet," depended on quick wits and elaborate disguises to arrange a "sting" to recover modern paintings stolen from a Paris gallery. Collet eventually got his paintings, but he had good reason to fear for his life at one point, when a gangster burst unexpectedly into a hotel room before Collet had a chance to arrange his wig.

Like a good detective novel, McLeave's stories are packed with intriguing characters. One is Kempton Bunton, an eccentric Englishman who stole Goya's portrait of the Duke of Wellington from England's National Gallery as a political protest. Another is Paul Constantin P,etridMes, whose decline was as precipitous as his ascent. Beginning as a goatherd on Cyprus, P,etridMes worked his way to Paris, where he rose from being a tailor to being a millionaire dealer with exclusive rights to the work of artists such as Utrillo. Finally, after a sensational trial, P,etridMes was convicted of fencing stolen paintings and sentenced to four years in jail.

Whether you read McLeave's book as a serious examination of art theft or simply as a collection of superb detective stories, you won't be disappointed. On either level, it is a marvelous book.