Barbara is believably repellent but much of her acerbic commentary is dead-on, and many of us would love to treat bureaucratic paper-shuffling with the open contempt it deserves. In the book, Heller gives Barbara more "devastating" speeches on various topics: the "unrelenting sanctimony" and "titillated fury" of the press coverage of statutory rape cases; her colleagues' "do-gooding fantasies" of "making a difference"; the tendency of "bleeding hearts" to concoct "soppy rationalizations for delinquency". Marber understandably had to trim them because onscreen they would probably sound smug, editorializing, as if we were supposed to like Barbara because we agreed with her.

When it comes to Barbara's early comments about Sheba's sense of entitlement, they are devastatingly right and funny, even if tonally off (too much feeling invested). But let's be frank, even when Barbara's comments descend to meanness — with respect to Sue Hodge and Ben — it's possible to identify with her because you know her disappointment has cut her off from other people and she has no idea what to do about it. Heller has constructed character with classic novelistic scrupulousness and Marber, whose original work is rather more vulcanized, fully respects it.

The narration goes back to the beginnings of naturalistic prose fiction in the epistolary novel, replicating every nuance of the character's personality in her own voice. At the same time, however, despite Barbara's "wish to be as rigorously and unsparingly truthful as possible" about herself in both book and film, we gather so much more information about Barbara than she intends to impart or would acknowledge as true that she is also that distinctively modern-ironic creature, the unreliable narrator, in the tradition of Ford Madox Ford's John Dowell and Nabokov's Humbert Humbert. In fact, Barbara is no less an object of irony than the people she describes so scathingly, and as much as any movie I can think of Notes on a Scandal balances the audience's compassion for, amusement at, and aversion to its protagonist.

Thus, what Barbara experiences as intolerable vulnerability looks like predation from the outside, and the moviemakers don't press us to resolve our ambivalence. Still, Notes on a Scandal is more fascinating the more you can identify with maddening Barbara — to see yourself as others may have seen you at those times when you have projected your own far-fetched hopes onto someone else, or made demands on people who don't realize you think they're offering what you've tacitly accepted as yours. Identification with Barbara darkens the outré anecdote into mourning shade. One of Marber's very best additions is Polly's line when she sees Barbara coming to speak to her mother after the scandal has broken: "Oh, Jesus wept! The spectre at the feast!" At certain times someone might have said this about almost any one of us with equal justice.

It also makes a huge difference that we do not have the same access to Sheba's interior as to Barbara's. If we did, the temptation would be too great to identify with the pretty one and thus excuse the affair that puts her in Barbara's clutches, which would be to turn naturalism into melodrama. At the same time, the movie's Sheba is not the baffling creature she is in the novel, who ends up a husk, in Barbara's keeping. The movie's Sheba had to be different from the book's shifty, perverse, and arrogant adulteress, because any actress has too much presence to be that creepy without putting us off the story.