Many of America's biggest music acts follow one of two extreme paths: They either hang around for so long that we can't imagine pop culture without them (think the Rolling Stones, Elton John, U2, or Madonna), or they have an explosive and ephemeral supernova-like career — burning twice as bright and half as long, as Lao Tzu would say. Think Avril Lavigne, Mandy Moore, Hanson, fun., or Jewel.

Britney Spears has somehow managed to follow both paths simultaneously.

It was nearly two decades ago that Spears donned a Catholic schoolgirl uniform for her 1999 hit "...Baby One More Time" and simply dominated popular culture. She burned so brightly, speeding from Mickey Mouse Clubhouse member to sexpot pop star. Her debut album sold over 30 million copies internationally and went platinum 14 times. Spears' second album is one of only 20 albums to ever sell more than a million copies in its first week.

But soon enough, she seemed to flame out, shaving her head, driving with a baby in her lap, smacking the window of a paparazzi S.U.V. with an umbrella, and just generally unraveling before our eyes.

None of that ended her career. She rose. She fell. And then she rose again.

Now, with her ninth studio album, Glory, due out Friday, Spears is somehow still everything she was in the late '90s and early '00s. But now she's also a comeback kid, a sympathetic human we can't help but root for.

This is perhaps the biggest difference between Spears and other celebrities who have taken tumbles in the public eye: She never tried to manufacture a new image to erase all of her past struggles. Britney Spears is unapologetically Britney Spears. She'll eat fried chicken after shooting the cover for the fitness magazine Shape. She still hasn't gotten over being shy about meeting her fans. She's often overcome by goofy expressions when she poses for photos. She'll get all dolled up for the red carpet and performances, but she has no problem going to lunch in sweatpants and Uggs.

But Britney Spears is more than just the queen of pop turned human. She's hung onto that special something that made her pop royalty, as evidenced by her regularly sold-out shows in Las Vegas. Some of it is nostalgia. Fans who listened to her on the school bus are still, all these many years later, more than happy to turn on her latest jams as they drive their own children to school. She reminds us of youth and vitality: Watch the music video for "Toxic" and be mesmerized and invigorated by Spears snaking around in a bejeweled jumpsuit. Put on "Oops!...I Did It Again" and realize you still haven't forgotten Spears wandering around Mars in that skintight red jumpsuit.

I was eight when Spears' first album came out. All the cool older kids would bring their boomboxes on the bus so we could listen as we rode to and from school. I listened to "Lucky" over and over again as I practiced a routine for my one and only performance as a jazz dancer. When I finally got my driver's license, the first song I turned on in the car was "Gimme More." I screamed the lyrics: "It's Britney, b-tch!"

When I turn on Britney today, it doesn't feel like just a throwback. Her music is versatile. I've listened to "Oops!...I Did It Again" at both a French bistro in New York City and in the grimy basement of a fraternity house in Indiana and yet, somehow, the song didn't seem out of place in either location. While some songs become inextricably tied to a time and place by being so popular in a specific moment (I guarantee that if you hear Carly Rae Jepsen's "Call me maybe," you will think about the summer of 2012), Britney's songs seem to have escaped that trap.

Spears' latest album isn't just the latest comeback attempt of a washed-up pop star; it's the latest installment in the story of a hugely successful pop star who has managed to maintain impressive durability, time and time again, without ever really losing her authenticity along the way.