“The Perks of Being a Wallflower” is wistful, witty, romantic and sentimental, a “Breakfast Club” for the new millennium. It’s not high school as it really was and remains today. It is high school as it really should be.

Writer-director Stephen Chbosky, adapting his own novel, presents a version of those years that is equal parts hopeful and cruel, with complicated, fragile kids with deep dark secrets and great, unrequited loves. The unpopular are protected from bullies by kind strangers, their peers, the ones who will become their “tribe.”

Logan Lerman stars as Charlie, the shy, bookish kid the others whisper about as the new year stars. Something awful happened to him, and to those around him. Even his family walks around on eggshells when Charlie’s in a brooding mood.

Which is often, as Charlie keeps a glum diary in the form of letters to a “friend,” narrating the life he leads as he enters high school.

But on that very first day, he sees her — a senior. And Sam (Emma Watson) is “the kind of pretty that deserves to make a big deal out of itself.” The fact that she doesn’t adds to her charm. And her welcome of this “wallflower” to her circle of friends is an act so offhandedly generous that a boy would remember it the rest of his life.

There’s Mary Elizabeth (Mae Whitman) and “Ponytail” Derek (Nicholas Braun). And most special of all is Patrick, the hard-partying, wiseacre philosopher king (Ezra Miller). Patrick is actually the one who sees potential in young Charlie and who sets out to show him the ropes.

These aren’t sitcom fantasy teenagers, they’re kids discovering their sexuality and experimenting with the things teens experiment with.

Charlie tries to fit in, tries to date, tries to hold his alcohol and not be a rude drunk the first time he drinks. We’re treated to awkward versions of “Truth or Dare,” cliched coming-out moments and jock bullying episodes.

And Charlie pines, pines, pines away for the beguiling Sam, who is, of course, dating Mr. Wrong.

Chbosky isn’t above peppering his portrait with the standard ingredients of such coming-of-age movies — kids into “kitschy” rock ballads, token shoplifter characters and the like.

“The Perks of Being a Wallflower” has a touch of that “Glee!” zeitgeist, the message that “It gets better” that so many kids need to hear. But what makes it close to a classic is the idea that even after it’s gotten better, we’ll warm to the best moments of our adolescent past and revel in every romantic memory, and we’ll cling to even the ones that scarred us.