For Richard Linklater, Julie Delpy and Ethan Hawke, the goal of three unique films – 1995’s “Before Sunrise,” 2004’s “Before Sunset” and 2013’s “Before Midnight” – that have followed the lives of Celine and Jesse, a pair of love-struck individuals, has been to make viewers feel like they know them. These are people trying to be understood, and the idea is “to get in on their communication,” as Linklater puts it. The films have aimed to depict Celine and Jesse as fully as they can, and the result has been one of the most singular on-going cinematic experiences in the modern canon.

To that, Delpy adds that a desire for complexity has been at the forefront. “They’re not melodramatic,” she says. “It’s kind of real and a very small window in the life of these people. It’s very important not to make them flat characters.”

Celine is unusual in that the opportunities to convey such a complex female character are so few and far between, particularly in the Hollywood sphere.

“The problem, probably, is very insidious,” Hawke says, “which is that young women are told at a very young age that what’s most interesting about them is being pretty. It’s a kind of soul-gutting thing to do to our young women. Whereas men are never taught that. The man who overvalues his looks is really sneered at. If you just flip through the channels and how often you see a woman disrobing in some way or dead or in some state of violence being put upon her, it’s shocking. It’s rare to see a woman not in one of those positions. So that’s what’s so remarkable about Celine. And also she’s a flawed person. It’s not a glamorized portrait of a woman. It’s a dimensionalized portrait.”

It was obvious to everyone involved from the first film that Celine was heading in a direction that is not a simplified version of a human being. Linklater adds by way of caveat that it’s rare that you get this sort of latitude to express a full like, but nevertheless, says Hawke, “I think one of the things Rick and Julie and I are most proud of is Celine, just what a fascinating figure she is.”

The logic behind the first film certainly didn’t necessarily make specific room for sequels. It was just an independent venture with three creatively motivated artists painting a portrait with passion. When the trio came back together for Linklater’s animated feature “Waking Life” in 2001, which featured a brief interlude with Celine and Jesse, that got the gears turning on revisiting the story.

“That’s when we looked at each other and said, ‘Maybe we should do it,'” Linklater says. “That was the big leap, doing the second film. Committing to that in the vacuum of no one wanting it, except three people and maybe Martin Shafer at Castle Rock. It’s the moment we realized Jesse and Celine are still alive that we have something to express through them at a new phase or where they are in life. And it’s not that conscious. It just bubbles up amongst us and it’s when we realize we’re all on the same page, what the movie would be.”

What’s interesting is that each film has mirrored the film industry and where it has been with each release, Linklater says. “The first film, while only a $2.7 million film, was distributed by a major studio, Columbia Pictures, through Castle Rock,” he says. “They had a deal there. Small release, but studios would release a small film, it’s worth it to have in their library. The second film was Warner Independent, gone, but an indie release. And then this film, we had no industry financing whatsoever. It was like private equity money, then acquired by Sony Pictures Classics, thankfully. We’ve had similar results with the three films, but who financed it? Three very different things.”

The collaboration since “Before Sunset” has been one that credits Delpy and Hawke as writers on the projects as well. The three were nominated for a Best Adapted Screenplay Oscar for that film and have just received a WGA notice for “Midnight.”

Leading into the third film, Hawke sat down and watched the first two back-to-back. What it did for him, he says, is unlock the tone. “Those movies have a unique tone and they can withstand a certain kind of humor and not another kind, and a certain kind of cynicism but not another kind,” he explains. “There’s a unique world to those first two movies that the third one needed to fit into and then push beyond. So you can’t break the tone or the spell dies. And what’s funny is it changes who I thought Jesse was when I played him in 1995. It’s different than how I look at him now. What I thought was confidence I now read as arrogance and insecure. Lots of things change.”

On the writing recognition he and his partners have received over the years, he surmises that what people probably think is most unique is what they’ve done on the page. After all, “most of these movies would be kicked out of any decent screenwriting course in America,” he says. “They don’t follow any of the necessary rules. The idea of collaborating on a screenplay with your co-star would be rare, but to do it three times in 18 years, it’s particularly rare. And it’s become a great experience for us.”

It feels a lot like getting a band back together every time, he says, and the bar is raised whenever they step back up to the plate. The fantasy and romance of “Before Sunrise” gave way to the added complexity of the tête-à-tête in “Before Sunset,” and now, “Before Midnight” takes the stakes to a whole new level as a full-on battle of the sexes is waged.

With that in mind, it’s interesting that “Midnight” is the first of the three that features any form of nudity, as Delpy launches into the argument that takes up the film’s third act topless. She says it’s funny, because no one in France ever asks about that, but it’s nevertheless indicative of the spiked level of realistic intimacy the films have entered into.

“Here a lot of people ask me the question and say, ‘Oh, don’t you feel objectified,'” she says. “Little do they know I decided as much as those guys did! It’s also there’s a certain strength in a woman being naked starting an argument. I always remember that scene in ‘Short Cuts’ of Julianne Moore, the other way around, screaming at Matthew Modine. It’s kind of like, ‘Wait a minute. We’re starting an argument but this person is naked.’ It’s kind of distracting and at the same time real and I think it does something to your brain, like, ‘I’m in a real fight. This is not a Hollywood fight. This is not a movie. Those people are fighting.'”

Adds Linklater, “That scene starts out a love scene. People call it the fight scene but it certainly doesn’t start that way. Like a lot of adult things, things swing kind of quickly. The moods, once you know someone, you can go from a great thing then one comment sends you down this alley and then it’s hard getting back out of it. When you’re falling in love with someone, it’s different – confirmation bias. You’re just looking for the connective tissue, what turns you on about someone, and everything’s great. But longterm you can go the other direction. It was satisfying when people liked this one as much as the ones before because it’s a less sexy era in your life. You’re not falling in love. You’re not breaking up. It’s less dramatic.”

But it’s all part of the reality they’re looking to forge. That’s also why Linklater prefers to shoot so many of the films’ scenes in long, extended takes, capturing all of the little nuances of performance and breaking the usual film language.

“It’s to make it not seem constructed,” he says. “Even though it couldn’t be more elaborately a construct, scripted to the gesture.”

“When I first saw ‘Dazed and Confused,’ I thought, ‘You know what? Anton Chekov would love this movie,'” Hawke says. “What Rick is going for is exactly what Stanislowsky was trying to teach 100 years ago. It’s getting rid of acting. Just getting rid of it. Why they would rehearse those plays for years was so they could stop performing.”

On that note, the actor remarks that Linklater – with whom he has now collaborated on eight films, including the upcoming “Boyhood” – is developing into one of the great filmmakers of our generation.

“It’s been one of the most rewarding aspects of my professional life, to watch that happen,” he says. “When he first burst onto the scene in ‘Slacker,’ he was a really interesting voice. But a lot of times a voice rings out like that and never deepens or matures. Watching Rick grow and his compassion and his wisdom, he’s evolving as a person and seeing things more deeply.

“And he’s such an unflashy director. He’s so simple and what he finds dramatic is so not in fashion today, you know? People want their movies to look like ads and they want everything to be glamorous, but he’s kind of allergic to glamor. He’s almost even allergic to drama. Whenever drama is highlighted and spruced up, it’s almost saying that life isn’t enough. It’s not enough to be alive and spinning on this Earth. You have to be a CIA agent or involved in a helicopter crash. And Rick is the opposite of that. He sees daily life as infinitely fascinating and full of mystery. That’s a wonderful viewpoint to be around. I love seeing life through his lens. It doesn’t need any magic on it. Life is magic enough.”

There are two upcoming opportunities to see the “Before” trilogy in all its glory. The series is currently screening at New York’s Lincoln Center along with “Waking Life” (right next door to the theater where Hawke is currently performing in a production of “Macbeth,” ironically enough). That series runs through Friday, Jan. 10. Additionally, the trilogy will be screening back-to-back on the closing day of the upcoming Santa Barbara International Film Festival on Feb. 9. Linklater, Hawke and Delpy will be on hand for a Q&A.