(CNN) -- For a "Wallflower," Stephen Chbosky's Charlie has quite a reputation.
The character, a sensitive 15-year-old high school freshman who initially keeps to himself, was first introduced to a generation of readers in 1999 as the protagonist of Chbosky's novel, "The Perks of Being a Wallflower." Since then, he's become just as famous for being too risqué for some classrooms as he is for endearing himself to a legion of fans.
In a series of letters addressed to an anonymous reader, Charlie describes the disorientation of losing a friend to suicide, the ways high school can feel like an experiment in isolation, and, at the heart of the story, his bond with older students Sam and her stepbrother, Patrick.
Now, 13 years after readers first met him, Charlie is in theaters this weekend in an adaptation written and directed by Chbosky. The movie features actors who've appeared in versions of other young-adult books, such as Emma Watson (the "Harry Potter" series), Logan Lerman ("Percy Jackson & the Olympians: The Lightning Thief") and Nina Dobrev (the CW's "The Vampire Diaries").
But there aren't any spells or mythological beings in Chbosky's tale -- there's just Charlie, the shy, introspective loner who finds acceptance within Sam and Patrick's circle of friends.
The great thing about Chbosky's story, actress Dobrev said at a recent screening, is that while it focuses on the turmoil of one high school freshman, it's nonetheless relatable.
"It makes you realize that everyone's kind of the same," she said, noting that all have a coming-of-age story that's seen love and pain, laughter and heartache. "Even though you feel like you're the only one going through it at the time, everyone has at one point or another," she said. In the end, Dobrev concluded, "Perks" shows that we're all misfits in our own way.
Charlie's early '90s-era high school experience touches on drugs, alcohol, sex and abuse, and at the time of its publication, the book was one of many examinations of the darker side of the teen experience, said Vicky Smith, children's and teen editor for Kirkus Reviews. What set it apart from the rest was its voice.
In the late '90s, "there was this wave, of what it felt like to a lot of people who worked with kids and books, of really depressing books," Smith recalled. "There was a continuum called the 'teen problem novel,' the novel about teenage pregnancy, and the novel about cutting, and the novel about anorexia.
"Right around the end of the '90s, a lot of those books, they were by and large really well-written, but they were really bleak. And 'Perks of Being a Wallflower,' while it's not really a laugh riot, was still funny enough and different enough from those incredibly bleak ones to catch a lot of people's attention."
It also didn't hurt that it was published by MTV -- back then home to "Total Request Live," Britney Spears and "Daria" -- through Gallery Books' Pocket imprint, which gave it an air of youthful understanding.
"('Perks') resonated because at the time, it was dealing with issues that weren't really in the mainstream," said Louise Burke, executive vice president and publisher of Gallery Books.
By today's standards, "Perks" might seem low-tech, but the novel hasn't lost its relevance, appearing at No. 16 on NPR's 100 best-ever teen fiction poll this summer and hitting No. 1 more recently on a New York Times' best-seller list.
"The teens that I speak to really love that these issues are being dealt with but it's not overdramatized," Burke said. "It's interesting that a book published so long ago is even more relevant now."
Add in the strong reaction from schools and libraries -- "Perks" is no stranger to the American Library Association's list of frequently challenged books -- and the book was "viral" before anyone even knew what that was, Smith said.
"It had that hand-to-hand, pass-along effect that books (that) kids would get from their teachers or librarians don't have," Smith said. "My daughter is in high school, and she wanted to read it before the movie came out, and I do think it spent a little bit of time getting passed around the cabins at her summer camp."
That peer endorsement from a friend was also how Marah Eakin, now 31, first picked it up in 1999 and became a fan.
"I had just started college," recalled Eakin, music editor for culture site The A.V. Club. "And I remember feeling like, 'These people understand me.' "
She was one of those kids "who listened to college radio," she joked, and while she might have wished to identify with love interest Sam or witty Patrick, it was the sensitive but openhearted Charlie with whom she connected.
"I think that's a universal feeling. You could be the class president, but you still feel like people don't entirely get you," Eakin said. "I don't think that ever really changes, but it does go away a little bit."
Rereading it as an adult, she said she can see why it's a book meant for a younger audience -- its earnestness and angst being out of step with grown-up sensibilities.
But "the fact that it's stood the test of time for 13 years is important, because the YA marketplace turns so fast; it turns on a dime with trends," Eakin said. "I think that this (book) still existing is a credit to Stephen Chbosky."
And that persistent fondness for "Perks" is "one of the things that makes a classic," Smith said. "As the first generation of 'Perks' readers starts having kids and seeing them grow up on their own, it'll be interesting to see how freely they share it. ... I think 'Perks' has a good chance of experiencing that kind of generational longevity."