Like virtually any other greatest hits album, it has some bonus materials. There are from several remixes, none of which are too good — for example, the Darkchild Remix of “Overprotected” is a clattery, feedback-laced affair. Spears also releases several previously unheard songs, such as the generic “I’ve Just Begun (Having My Fun)” and equally dull “Do Somethin’.”�The most hyped song is “My Prerogative,” an electropop cover of a Bobby Brown song — with lyrics like “I don’t need permission/I make my own decisions,” it sounds like an immature, defiant finger-flip at the world. Good luck with that.

Usually “Greatest Hits” albums are put out for one of two reasons. Either a band/singer has been around for eons and has enough glorious songs to fill an entire album, or the label they are/were signed to is trying to cash in. For the latter, think “Best of Mandy Moore,” which Ms. Moore had nothing to do with. Sadly, Spears’ “Greatest Hits” album is neither — instead, it feels like an effort to keep her at the forefront of music store displays.

Her music is pretty standard for whatever kind of pop is attempted — polished and overproduced. And, I might add, very predictable — virtually every blip and note can be detected before it’s heard. While “Toxic” has a halfway decent beat and some electric violins, Spears strikes out with her newer pop melodies, especially the ones that sound a lot like No Doubt covers.

Her image also veers wildly through the various songs, starting off with the sound of a giggly teen who has done something naughty. Then she’s launching into the more sexual stuff, especially in the horribly-written “Outrageous” (”Outrageous!/My sex drive/Outrageous!/My shopping sprees….”). But it doesn’t feel genuinely sexy — rather it feels like a little girl dressing up in mommy’s lingerie.

And Spears’ vocals have never been too good — her early material displays a voice that is pretty typical for a teenage girl. It has little range, and it’s a sort of breathy, thin voice. That doesn’t last — her voice deteriorates over the more recent tracks from her fourth album, becoming drier and more computerized. The sound peaks in “My Prerogative,” where Spears sounds like a congested robot.

Everyone has an opinion on Spears’ much-publicized love life, but the quality of her pop music is pretty clear. While her early material was innocuous in a teen pop sort of way, her pop ditties have only deteriorated with time.