The Mona Lisa was indeed briefly stolen from the Louvre in 1911--by an unhinged ltalian patriot named Perugia, according to art-history books. Here, however, in a sly, offbeat caper-thriller, Page (The Pilate Plot) offers a fictional version of what-really-happened--starting with an elaborately arranged 1909 meeting between old, ugly J. P. Morgan and super-super-thief Adam Worth, a 40-ish Lithuanian Jew who can disguise himself at will. Morgan wants Worth to steal the Mona Lisa for him. (""A man could do anything in front of her. I intend to die in front of her."") Worth agrees, takes a $1 million down-payment (on a $5 million fee), and disappears for two years--using the money to fake his own death (even Morgan is fooled) and create a whole new identity for himself. So now, in 1911, Worth is in Paris, with a series of convincing aliases and new wife/henchwoman Angelica. (He married well-born Angelica just as window-dressing but fell in love with her when she turned out to be a kleptomaniac.) Together Worth and Angelica, while rowing on the Seine, devise the theft scheme--which involves a diversion (Angelica), a museum laborer in disguise (Worth), and an airshaft escape-route. Meanwhile, however, Morgan has hired a new thief to steal the Mona Lisa; Worth is forced to indulge in some amusing tricks and some vivid, nasty violence; eventually the heist does go off pretty much as planned. And the final chapters involve a series of forgery/real-thing exchanges, a spot of smuggling, the creation of the Perugia hoax (via blackmail), and lots of cat-and-mousery between ever-suave Worth and a very cool French detective. (They play snooker together.) Too oblique and arch for an action-oriented thriller audience, perhaps, but crisp and intriguing fare--with distinctive slivers of period atmosphere (trains, bordellos, restaurants)--for sophisticated fans of dark-edged, mocking derring-do.