MR. WRONG.

For a few minutes before Neil LaBute's "Fat Pig" begins (at the Lucille Lortel, directed by Jo Bonney), the supersized woman of the title stands before us, munching a slice of pizza and reading at a tall table in a busy restaurant. She is Helen (the compelling Ashlie Atkinson), a librarian who is in the neighborhood of two hundred and fifty pounds--not a neighborhood she looks to be leaving anytime soon. The moment is typical of LaBute's subversive prowess. He makes us stare at her. LaBute, who is a connoisseur of unsettling emotion, knows that Helen is a type whom the audience rarely scrutinizes on stage or in life; he plays off the public instinct to avert the eye. If beauty carries with it the magical sense of being blessed by the gods, as Goethe says, obesity suggests the opposite irrational aura--being damned in the flesh to be outcast, reviled, untouched.

Here, when a man enters with his tray and says, apparently to himself and about the room, "pretty big," Helen is quick to pick up on a hint of abuse. She calls him on it, and a conversation begins. Most playwrights don't earn their ending; LaBute, it seems to me, doesn't earn his beginning. However, such is his gift for dialogue that we soon become fascinated by these strangers. He is Tom (the excellent Jeremy Piven), a successful executive--neat, careful, well-spoken, charmingly average and conformist. When asked about his best qualities, Tom answers, "Plays well with others." Helen is a solitary who has had to learn to be resourceful and brave. She has a penchant for war videos. "That's not very 'girlie' of you," Tom says. Helen replies, "You're probably just dating the wrong kinds of girls"--a startling riposte that turns out to be all too true and makes Tom look at her in a different way. She is humorous and smart and sometimes brazenly direct. "I don't only eat. I can be coaxed into doing other stuff, too," she says. There is a rapport. He gets her number. She leaves. Then, in the sort of theatrical choice that makes LaBute such a fascinating writer, Helen returns to speak her heart. "Even to talk on the phone would be fine. . . . Just don't be afraid, Tom. I guess that's why I came back here, was to say that," she says. "Please do not let yourself be afraid of me or of taking some kind of blind chance, or what people think . . . because this could be so great." This superb speech allows us to see her understanding of him as well as of herself. She acts on her desires. She's clear-eyed and grownup. Tom, we soon learn, is one of those stuck adolescent souls who play life not to win but to not lose. His repressed heart is unable to define its desires. He'll do anything for an easy life. By contrast to plus-sized Helen, Tom isn't so much a will-o'-the-wisp as a wuss of the will.

LaBute's psychological terrain is the punishing slippery slope of ambivalence. In his hands, this bedevilling state of spiritual stasis comes with a distinctive mystifying sound, a sensational hemming and hawing, which poetically betrays the mind boxing clever with itself. Tom, who is sexually unresolved, is a master of verbal ducking and diving; it's a sort of linguistic ...