That's funny. I just bought that book. Haven't read it yet, though.
It's a work of fiction though. Here's an interview with Chbosky where he talks about his process of writing it:
I agree with editor! I like that book in that aspect because you don't know if "Charlie" is a real person, a work of fiction, or the author himself...
the mystery makes it all the better. [:
One of my favorite books...it's what my personal screen name and email address come from.
Charlie isn't real, and it's not real journal excerpts. But it could be. And that's what makes the book my all-time favorite.What's a way I can describe blue eyes in my story?
No, the book "The Perks of Being a Wallflower," is a complete work of fiction. It is not based on events that actually happened.
The author, Stephen Chbosky, has said that while the book is personal to him, it is not 100% autobiographical.