What makes Becky climb?

Well, Becky Sharp climbs for the same reason Sammy Glick ran and all those other strivers strived and hustlers hustled: Need. Hunger. Anger. And, most of all, the furious desire to be somebody.

But the larger point is that as she climbs, she penetrates and as she penetrates she illuminates and in the end, her creator, William Makepeace Thackeray, has exposed a whole society. The novel, of course, is "Vanity Fair," an example of 19th century genius at its finest, one of those big, fat, sprawly books with a thousand characters and a battle, a ball, lots of parties and celebrations, usually a duel or two and sometimes a deathbed declaration and at least 17,500 semicolons. Too bad they don't write them anymore. But here's Mira Nair's fine movie version of the 1848 book, in all its glory and scope and wit.

It goes everywhere, it sees everything in Regency England, and at the center of it all is bold, brash, opportunistic and yet wonderfully gifted Becky Sharp. You'd think that such a creature would be a natural in movies, and yet on the big screen only Myrna Loy (in 1932) and Miriam Hopkins (in 1935) had played her and neither the movies nor the performances are much remembered. What a pity. Was there ever a role better made for the young Bette Davis? In the '40s, tough little Barbara Stanwyck would have been perfect. After the war, the movies flattened out the women, made them softer and bustier and more neurotic and the possibility of a zingy "Vanity Fair" vanished.

Thus it's no surprise that the role of Becky in post-feminist 2004 goes to the one modern actress with a classic '30s face and zest: the American Reese Witherspoon, who makes a far, far better Englishwoman than Renee Zellweger did in "Bridget Jones's Diary." Witherspoon's simply terrific, and it's amazing how quickly and easily she sheds speculation that she was too modern for the role.

Somehow, Witherspoon makes Becky likable as well as admirable. You sense this young woman, born in poverty in the slums, understands the hypocrisies of her age more acutely than do those who are a part of its system, and you respect the way she plays its vanities off against each other to engineer yet more prosperous relationships, until at last she comes to be the favorite of the Marquess of Steyne (Gabriel Byrne). Witherspoon is perky but never simply perky; you see a wicked gleam in her eye and a sense that she enjoys the game of climbing, even when it deposits her, ever so briefly, at the shabby estate of a country squire noted for both his stupidity and his greed. But that's all right, he's not very clean either.

The plot is set up neatly by Thackeray to parallel the rise and fall of two young women, the good Amelia Sedley (Romola Garai) and the bad Becky Sharp. But of course we like Becky far better, because she's active, dynamic and ambitious, while poor Amelia is long-suffering and sanctimonious and a perpetual victim, frequently of herself. Is there anything duller than a good girl? One of the clever tricks the movie plays is a gambit at movie's end when Becky saves Amelia from Amelia's worst enemy, Amelia.

In any event, Becky, the daughter of a starving artist and a somewhat dubious French woman (stories conflict), grows up a poor orphan in a Miss Pinkham's posh finishing school, where she learns the ways of the aristocracy under the stern mandate that she can never be one. But that doesn't stop her. She sets out to win her way on charm and guile and up and up she goes.

The trip takes her primarily into the tribe of men, for it is men who control society, while the women only remark upon it. Becky's love life -- or, since actual sex probably never occurs, her network of ties and flirtations and respites of favor and deserts of disfavor -- are immensely complicated. Briefly, when she's visiting friend Amelia, she meets Amelia's betrothed, sexy George (Jonathan Rhys-Meyers) who is quickly smitten with her wit and beauty, a disturbing development. Meanwhile poor Amelia is being earnestly wooed by the noble worship of clumsy Captain Dobbin (Rhys Ifans). Then Becky steals the heart of another officer: Rawdon Crawley (handsome James Purefoy) who happens to be the favorite nephew of her new employer, the wealthy Miss Matilda Crawley (Eileen Atkins, delicious as the tart-tongued old biddy). When Rawdon marries Becky, the two are cast out and disinherited by Miss Matilda.

Along comes Napoleon, that nasty man, who escapes from Elba and heads for his Waterloo at a place called, er, Waterloo, where all the men fight after a fancy ball at which all the women and all the plots, counterplots, intrigues, heaving bosoms, golden ringlets, thigh-high cavalry boots (really cool, by the way) are present.

Some survive the epic fight, some don't; Nair re-creates it in a tableau of the fallen in just a few seconds. It's reminiscent of that scene in "Gone With the Wind," when Victor Fleming's camera cranes backward farther and farther and the shot gets wider and wider until the whole world seems filled with the dead and the dying. It's one of Nair's frequently brilliant images that sums up incisively a moment or an event.

After the war, with Regency decadence in full blossom and debauched George IV on the throne (so much fun before dour, grim Queen Vicky doused it all in a cold shower of rectitude), Becky catches the attention of Steyne, a bounder and cad himself, as it becomes evident that poor Rawley just isn't going to make it in civilian life (he's a gambler). You have to give it to Becky: She seems to become what might be called a professional mentee, less than a mistress yet more than an assistant. It's a delicate transaction but negotiating it is her genius: She's always got a mentor, a believer in her who sponsors her, until she trades up. She's always the outsider on the make; love seems only a distraction, something for the well-born.

Which itself brings us to another curious issue. This is totally an outsider's view of a decade of English history. Nair is an outsider herself, even more so than the climber Becky Sharp and the American Reese Witherspoon. She's Indian by birth and has always been fascinated by the interface of cultures. Her first non-documentary film was the widely praised "Salaam Bombay!," and her best film was probably "Mississippi Masala," which watched a young Indian woman and an African American have an affair in the modern American South. She has a profound sense of her own culture, even as she so effortlessly evokes Western culture.

This gives her "Vanity Fair" an unusual spice -- you might even call it a curry. Her vision of English society in the early 19th century is positively alight with the flavors of India. There's very much a sense in this picture of the omnipotence, the power of the abiding Eastern culture over the usurping Western one. In some sense India is the mother-healer of the British empire as, ever so frequently, people go there for a sort of spiritual repair or healing. This dichotomy is particularly expressed in the cinematography (by Declan Quinn): India is hot and bright and lush and vivid, while old blighty is greenish and wet and dank. Without a word being spoken you feel the director's preference in the photography.

That's an irony that runs all the way through Nair's vision of "Vanity Fair"; the original book was set at the high-water mark of empire in the British century, when Britannia ruled the waves, pip pip, what ho, and all that jolly old fun; yet in this movie makes the point that even as England was capturing its empire, the empire was capturing England.

Vanity Fair (137 minutes at area theaters) is rated PG-13 for sexual innuendo and battle violence.

Reese Witherspoon is wicked and witty as the English social climber.Jonathan Rhys-Meyers is one of many men smitten with Reese Witherspoon.