The trailer for Teenage.

If you’re planning to see the new documentary Teenage, which is out March 14 in the U.S. and now showing in select cinemas in the UK, definitely bring a notebook and pen. The first time I watched it, I filled pages with notes on the teen movements I learned about! It’s based on a book of the same name by the British punk historian Jon Savage, which outlines the development of the concept of “teenagers” from 1900 to 1945 and the hidden histories of young people who made powerful contributions to society and culture during that period.

The movie, directed by Matt Wolf, lays out how Germany’s most infamous collective of young people, the Hitler Youth, was created by the Nazis in order to direct the power of teen determination in their favor. I loved the idealism of the German Wandervogel, a group of teens who longed to return to nature after the horrors of World War I; the tenacity of Hamburg’s World War II–era Swing Kids, who flouted the law and partied to verboten American swing music; and the unwavering determination of the White Rose, a student organization from Munich that fearlessly spread anti-Nazi propaganda (and whose members were eventually executed for their activism).

The coolest part of the movie, which also explores American and British teen subcultures, is how it subtly positions teenage girls as the ultimate revolutionaries, as in the stories of White Rose member Sophie Scholl and the British hedonist Brenda Dean Paul. Although the movie ends just after WWII, the world-changing powers of teenagers (especially teenage girls) that gathered force during the first half of the 20th century can lives on today, perhaps more than ever.

I recently spoke with Jon and Matt about their inspirations and goals for Teenage, the importance of taking young people seriously, and what has—and hasn’t—changed about teenage life in the past 100 years.

LAURA SNAPES: I find it hilarious when adults freak out over selfies, as if the concept of image-conscious teenagers were anything new. Your book and film tell the story of Brenda Dean Paul, a 1920s socialite who was notorious for being a narcissist.

JON SAVAGE, author: People talk a whole lot of crap. Brenda is a fascinating character. She published a wonderful biography in 1935, and a lot of the stuff in her section comes directly from that book.

And the footage of the Hamburg Swing Kids that you used in the film came from home movies, right?

Yes. I think it was shot by rich kids, since they had their own camera. It’s extraordinary that it exists. In constructing the film, we had a problem: During these stages of youth culture’s development, almost all the footage of teenagers was by adults, from an adult perspective, so if we were going to show the dialectic between the adult perspective and the teenage perspective, we had to get it from [teenagers’ home movies], diaries, and autobiographies.

We didn’t want the material to be a dry, adult voiceover–type thing where you’re being told. We wanted to place you in the state of what it was really like to be a young person in these particular times, places, struggles, and situations, and give you some emotional taste of that. Otherwise, [the story] would have been lifeless and dead, and being a teenager is very emotional—you feel things very keenly then. What happens in your adolescence and teenage years stays with you for the rest of your life.

Based on your research and your personal experiences, do you think there were times where teenagers were more valued in the wider culture?

Oh, god, no. It was all ghastly. I was 16 in ’69, at the tail end of the hippie thing, and I remember adults looking at me disapprovingly because I had long hair. I used to go around by myself a lot, and I’d scowl at them—I was pretty sulky. I remember feeling very disapproved of.

But of course there are always adults who want to encourage you, too. When I interact with adolescents now, I regard it as my job to pass on information—not to say, “Oh, we were much cooler than you.” That’s completely irrelevant. Each generation has its own circumstance and its own task.

I was a rural teenage girl who couldn’t find like-minded peers that easily, and alienation fed so much of my identity. Do you think teenagers experience isolation in the same way now that they can interact with one another online?

You’re always going to have alienated adolescents. That doesn’t change. If you can survive that without any major damage, it actually gives you a lot of power. When you’re a teenager, you’re tasked with engaging with your peers rather than your parents, and the next step is to disengage from your peers and form your own identity, which is absolutely crucial. It’s always the marginalized weirdos that I’m interested in—those are the people who come up with interesting ideas and good art. I never wanted to be normal. I thought it was so boring.