Premiering Friday in theaters and on demand, Unstuck in Time — screenwriter, producer and director Robert B. Weide’s new documentary about Kurt Vonnegut — is a film nearly 40 years in the making.

Weide first contacted Vonnegut about making a biography in 1983 and started filming in 1988. Over the years, the two became friends and intermittently filmed footage until Vonnegut’s death in 2007. As Weide and Vonnegut grew closer, the film became more difficult to finish. Weide’s original plan was a straightforward documentary. Having become good friends with his subject, would that even be possible?

The result is a film that manages to capture every facet of Vonnegut and even succeeds where many other films have failed — representing the magic of his words and the feeling of intimacy that generations of readers have felt while reading Vonnegut’s work.

I had the pleasure of speaking with Weide on November 11, before the film’s New York premiere screening at DOC NYC, America’s largest documentary festival. It was, as Weide pointed out, Vonnegut’s 99th birthday.

Excerpts from our conversation are below and edited only for clarity.

How does it feel to be premiering the film after working on it for so long?

Well, it’s a relief, really. A joy to me that it’s finished. I had serious fears for a lot of the past 39 years that it never would be completed. After (Vonnegut’s) death, I was treading water, not knowing what was going to happen. So the fact it’s finished now is a great relief to me.

There’s this sort of decompression period after I finish a film, where maybe I’ll find some clip of Vonnegut that I’d forgotten about or a quote of his. And part of me automatically goes into this “How could I fit this into the film …” But then I say “Bob, you’re done. You’re finished.” And being able to say that is a relief.

Has there been anything you found since finishing the film that you wish you could’ve added?

The only thing I really regret — and this is something I actually had, someone sent it to me but I never looked at it until afterwards. There’s a line of Vonnegut’s I knew about but had never actually found footage of him saying. He talks about how his intention is to warp young minds with humanity, and he’s talking specifically about high-school and college kids. Everyone I know who discovers Vonnegut finds him at that time — I did, with Breakfast of Champions — when they’re forming that perspective of the world. And he thinks that’s a good thing to do with young people — to warp their minds with lessons of humanity, to help them grow up to be decent humans.

But in a film like this, and all the material we had to look at when finishing it, it’s a challenge to get it down to the right weight. We went to two hours and seven minutes, which to me even seems indulgent. Thankfully, whether people are telling me the truth or I’ve found a cross-section, nobody has told me it felt long.

There are moments in the movie that show you with the sheer amount of research material you accumulated over time. Is there a plan for what you’d like to do with that material in the long run?

I haven’t thought about it yet. In the long run, I’d like it to be available to some institution or organization where people could benefit from it.

I was fascinated by the structure of the film, which mixes Vonnegut’s biography, your friendship and the story of you completing the film. At what point did you settle on that structure as you finished the film?

At the start, my intention was to make it a conventional author documentary, and that would’ve been fine with me at the time. As days turned into — as years turned into decades — it seemed impossible to go back to that sort of structure or format. He had become such a close friend of mine that it seemed journalistically dishonest not to disclose that. I wasn’t thinking hard about how the film would come out. I just kept filming him as much as I could when we could. After he died, the film really sat as I figured out how to go forward.

It was other people who convinced me that the story about me meeting my literary hero, and the evolution of how this friendship with him deepened so much over the years alongside my struggle to make the film, should be folded into the project. Mutual friends of ours suggested it.

And I was really reluctant to do that. I did not want this to seem like an ego trip or an excuse to show off how good friends we are. But it seemed the only honest way to do it. That’s when I brought in Don Argott, another documentary filmmaker, to cover the meta element so I could focus on Vonnegut and not attempt to interview myself and follow myself around.

The other thing that made it work for me was that this is how Vonnegut himself got out of jams any number of times. He appears in Breakfast of Champions and talks to Kilgore Trout. He does it a little bit in Slaughterhouse-Five. Timequake, that’s a book he struggled with writing for 10 years before finally settling on a structure where half the book is the novel and the other half is him telling us about his struggles to write the book. So that helped sell me on it. It was the Vonnegutian way out of it.

Speaking of Timequake: You mention in the film that you’re actually featured in the book, during the Timequake Clambake, when Kilgore Trout meets Vonnegut and many of his friends. Could you tell me more about the moment you first saw your name in it?

Well, sometimes when I’m in a bookstore, I still look for a copy of Timequake to make sure I didn’t imagine it. When I first saw it, these were unbound gallies, these were basically Xeroxed, typed pages — not hand-typed, but printed from a computer. These were unbound printed pages. I’d finish a page, put it aside, read the next. I was reading it in bed around 2 a.m. I did not expect it. I let out a holler. Nobody to talk to, as I was single at the time and it was two in the morning. I remember years earlier, in the introduction to Wampers, Foma & Granfaloons, Vonnegut mentions a letter he received from a young fan and I think he mentioned him by name. At the time, I thought that fan was so lucky. Exactly 20 years from then was when I read Timequake and saw my own name.

I know when he mentions you in the book, he mentions the adaptation of Mother Night you were working on at the time. Among the adaptations of his work, which are … not always great, your film is generally regarded as one of the better translations. What sort of advice did he give you when you were working on the film?

Well, I want to say that I do love the adaptation of Slaughterhouse-Five by George Roy Hill. I know people will say to me, you know, mine is one of the best, but I always say at least second to that.

I can tell you very specifically what Kurt told me, though: “The book is the book. The script is your script. You should not feel any obligation to devote yourself to the words in my book.” And what he said was very him: “Think of my book as a friendly ghost hanging around the house.”

In other words, it’s there. You can turn to it if needed, but you can also ignore it. He did, a couple times, give me suggestions for a line or two, some of which I used and some I didn’t. But really, he just wrote me and said “It looks like a great script.” He was non-territorial about his books. His feeling was that if someone makes a movie, good, bad or indifferent, the book is still on the shelf. And he was honest about how he felt about (the adaptations). He loved Slaughterhouse-Five and Mother Night, but the others were more of a mixed bag. But I know other authors who are more hands-on, and really, he wasn’t too concerned.

Well, I just want to thank you for your time today. I really loved the film.

Well, thank you very much. If you take a look at the Twitter feed for the film, I’ve posted something special for his 99th birthday.