You've probably seen them by now: Stark and imposing, white and bare, the bulk of the ads for 'Salt' have only the movie's title in large black lettering and a sliver of a woman's picture. There's no action scene, no cramming in of actors' names (see: 'The Expendables'), and certainly no quotes from critics eager to feed the hype. Yet while the campaign leaves much to the imagination, one thing is unmistakable: 'Salt' stars Angelina Jolie.

The mysterious marketing for the actress's new spy thriller, which opens July 23, fits neatly with the film's plot. Jolie plays Evelyn Salt, a CIA agent who goes on the run after a defector to the U.S. accuses her of being a Russian spy. Much like the 'Bourne' trilogy, 'Salt' plays on identity and perception, leaving us to wonder -- as the film's tagline suggests -- who is this lady, anyway?

'Salt' banks, of course, on the fact that not only do we know who she is (in real life, anyway), but that we'll flock to the movies to see her -- especially if she's going to kick butt and find redemption in a story laced with major sex appeal. But that's a big bet in a summer that's been a box-office letdown, thanks mostly to poor sequels and remakes, among other theories (which also include the combination of a tight economy and pricey 3-D tickets).