Sweeping from social comedy to historic melodrama, with a detour into epic romance, Mira Nair's adaptation of Thackery's 1848 novel covers much ground in two-and-a-half hours, and the shifts in tone can be jarring: One reel we're parlour-lounging with aristos named Sheepshanks, the next we're examining the corpses at Waterloo. But surely that's Nair's point, or one of them, in retelling the story of low-born but high-spirited Becky Sharp (Reese Witherspoon), who, always with a dazzling smile, claws her way onto the fringes of London society and fights to stay there. It's a visually handsome and pleasingly clear-eyed look at the hypocrisies of the upper classes and the politics of benefactors with agendas, smart dialogue included. Importing colonial exoticism from the near East, Indian-born Nair also riffs on the uses of outsider culture. Witherspoon's likable if not terribly deep performance leads a respectable ensemble cast including James Purefoy, Rhys Ifans and Gabriel Byrne.