The Perks of Being a Wallflower

"And in that moment, I swear we were infinite."

—The book's most famous quote.

The first (and so far^[when?] only) novel by Stephen Chbosky. It was first published in 1999.

The narrator, 16-year-old Charlie, is just starting high school as a freshman, having been held back a couple of years for reasons of being in the hospital due to being emotionally damaged. The novel primarily concerns Charlie's adventures in the '91-'92 school year, and is written as an Epistolary Novel, a collection of letters Charlie is writing to a friend-of-a-friend whom he was told would be a good listener. Charlie, who doesn't excel at much except reading, seems to be off to a bad start before two seniors, step-siblings Patrick and Sam, take him under their wing. And so begins Charlie's adventures into school, literature, dating, Sex, Drugs and Rock and Roll, teen pregnancy, suicide and The Rocky Horror Picture Show.

The book was well-received and essentially the literary version of a Killer App for its publisher, the newly-launched MTV Books. It has drawn comparisons to The Catcher in The Rye, primarily for being a pull-no-punches look at high school and for having a First-Person Narrator. It also placed 6th on 2008's List Of Most Frequently Banned Books, for similar reasons.

A movie, written and directed by Chbosky, was released in 2012. Logan Lerman and Emma Watson play Charlie and Sam respectively, and Mae Whitman plays Mary Elizabeth.

Tropes used in The Perks of Being a Wallflower include:

Ambiguous Disorder: Charlie is just said to be "emotionally disturbed".
Bittersweet Ending
Brutal Honesty: Charlie picks the worst possible time to invoke this when asked in a Truth or Dare game to "kiss the prettiest girl". He kisses Sam.
California Doubling: Averted. Most of the locations for the movie, right down to the theater where they see The Rocky Horror Picture Show, are filmed in their original locations in Pittsburgh.
Camp Gay: Patrick, mostly when contrasted with Brad.
Cool Teacher: Charlie's English teacher Bill.
A Date with Rosie Palms: Charlie learns about what masturbation is at one point. This leads to an incredibly narmful passage in which he describes it in awe opening one of his letters.
Double Standard Rape (Female on Male): averted by the nightmares Charlie suffers after being sexually abused.
Dysfunction Junction
Epistolary Novel: Charlie is writing these letters to someone. Evidently he just started sending them without any prior correspondence.
First Girl Wins
First Kiss: Sam to Charlie. She specifies that even though she has a boyfriend and sees Charlie strictly as a friend, she want his first kiss to be with someone he loves (see Rape as Backstory below).
Good Girls Avoid Abortion: Averted by Charlie's sister.
Invisible to Gaydar: Brad.
Jerk Jock: Brad has shades of this, and pretty much evolves into a full-fledged one when his dad catches him and Patrick and beats the shit out of him.
A Man Is Not a Virgin: Averted. Charlie is.
May-December Romance: While Charlie was held back a couple grades and should have been a junior, he's still a freshman dating a senior (Mary Elizabeth).
No Name Given: Charlie's sister never has a name mentioned out loud, nor do his parents or brother. And for that matter, there's hints that "Charlie" is a pen name adopted for reasons of anonymity (Charlie's sister has been named "Candace" in the film, probably for reasons of practicality).
One Steve Limit: Averted. Charlie's English teacher, Bill, shares a name with the limo driver for prom (Billy).
Rape as Backstory: Sam was molested, if not outright raped, as a young girl by a friend of her father. Also, Charlie's aunt was raped as a young girl, which led to her having serious psychological issues, which is why she herself molested Charlie.
Their First Time: Both versions are played straight: an unanticipated tryst is interrupted by something.
Twenty Minutes Into the Past: Published in 1999, takes place over the '91-92 school year.
Wanton Cruelty to the Common Comma: When learning how to punctuate, Charlie scatters punctuation all over that day's letter. The next day he apologizes (...it was funny at the time).