Like a fiction version of Michael Apted’s “Up” documentaries, Richard Linklater’s “Before” trilogy follows characters as they grow over the years, becoming older but perhaps not wiser. In “Before Sunrise” (1995) he introduced American Jesse (Ethan Hawke), an aspiring writer, and French Celine (Julie Delpy), a student, as the two met on a train and spent an evening in Vienna, talking through the night as they walked through the city and then went their separate ways, promising to see one another again. But they didn’t reconnect until nine years later, in “Before Sunset” (2004), as Jesse stopped in Paris during a book tour, promoting a novel based on his Viennese encounter with Celine and, now an environmental activist, she came to the event. Though married with a son, he was obviously unfulfilled, and their second long evening renewed the old sparks. Now, in “Before Midnight,” once again set nine years later, they’re a couple with two young daughters, living in France but vacationing for the summer in Greece with an elderly writer and his family. And though the setting seems like paradise, the relationship shows the on-and-off quality of marriages that swing between affection and antagonism.

Like the two previous films, this one has a beautiful locale to play with but is basically a long conversation. And it’s not a terribly happy one. Jesse, after seeing his son—who’s spent the summer with them—off at the airport for the return trip to his still furious ex-wife, drives back to the villa with Celine, and they bicker about the future. She’s frustrated in her work but thinking about taking a job that might be even more problematic. He raises the question about their possibly moving back to the States to be closer to his son. Nothing is resolved, but the episode shows her quickness to anger, his resort to sarcasm, and the propensity for defensiveness in them both.

The second act consists of a lunch at their host’s seaside estate with another middle-aged couple, along with a young relative of the writer and his girlfriend and an older woman. The conversation turns on male-female relationships, careening from jocular observations to poignant reminiscences of lost loves. Then the film enters its third act as Jesse and Celine find themselves in a hotel, where their friends have arranged for them to stay alone for a night. Here their conversation begins as an affable return to the musings of the previous two films, but soon degenerates into an extended argument in which each brings up long-standing complaints about the other and they wind up apart, though the final scene suggests at least a temporary rapprochement.

“Before Midnight” was written by Linklater, Hawke and Delpy, and the dialogue has the sharpness to be expected of well-educated, intellectual people without becoming pompous or unrealistically affected. It helps, of course, that it’s being delivered by Hawke and Delpy, who by now play off one another like tennis pros familiar with each other’s game and eager to exploit the knowledge. And that it’s directed by Linklater, who, together with cinematographer Christos Voudouris, records it all in a way that makes use of supple camera moves while recognizing the value of stabilizing static shots and doesn’t indulge in artsy touches for their own sake. The result is a film that feels naturalistic but not bland.

You don’t need to have seen “Before Sunrise” and “Before Sunset” in order to find “Before Midnight” perceptive and rewarding, but your appreciation of it will be immeasurably enriched by familiarity with them, because it represents the conclusion of a trilogy that, over the space of eighteen years, has subtly depicted the birth, growth and maturation of a man-woman relationship with its inevitable vacillations between affection, sacrifice, self-concern and acrimony. Consider the totality something like a sibling to Bergman’s “Scenes from a Marriage,” with this installment a descendent of “Who’s Afraid of Virginia Woolf”—but not really like either. The “Before” films really are sui generis, exceptional for that reason and many others.