"I couldn’t be a woman," Steve Martin once joked, "because I’d play with my breasts all day." Now he has written a novel about a young woman, but nearly the only thing he can imagine about her is wanting to play with her breasts. The Object of Beauty is a nasty exercise in narcissism, particularly in the narcissism of the famous.

Dark subject matter is conveyed with certain smart-assey detachment. Martin knows when to drop a joke in before things get too serious. Timing. Comedians have it.

“An Object of Beauty” follows the New York art world climb of Lacey Yeager. She is a charismatic character yet a very odd one to have emerged from the imagination of Steve Martin. Although Lacey is treated as this book’s main source of fascination, it’s less interesting to look at her point-blank than to look at her while wondering what Mr. Martin sees.

One aspect of this novel’s allure is the ambiguity with which Mr. Martin frames Lacey’s fierce, outsize ambitions. Is her story meant to be the appreciatively told tale of a canny New York predator? That of a relative innocent whose values change in the presence of vast sums of art-market money? Or that of a stylishly attractive dynamo who, with only minimal irony, recognizes herself in the monstrous goddess that Willem de Kooning painted as “Woman I?”

Is she an unalloyed opportunist? Or is she as intoxicated with art as she is with the leverage and entrée that expertise will bring? Is she stirred by art’s erotic power or just someone who sexually exploits the acquisitive passions of insatiable collectors? Does she share the collectors’ boys’-club competitive spirit (for surely this is a man’s world, at least in the way it is depicted by Mr. Martin)? Or is she just a woman who’s inordinately good at manipulating rich, credulous men? . . .