To truly appreciate all that “Love Letters” has to offer, just sit there and listen.

A.R. Gurney’s 1988 drama, now enjoying a vibrant revival at the Brooks Atkinson Theatre, has no set, so there’s not much in the way of distraction. Paired actors—Brian Dennehy and Mia Farrow are up first, in a rotation of stars who will perform through winter—simply sit side-by-side at a table, reading from the playwright’s disarmingly funny script.

There’s little for an audience member to do but stay motionless, perhaps close his eyes, and get carried away. If the epistolary drama is done well, you should be silently reminiscing about your own closest relationships, present and past, in no time.

I’m happy to report that “Love Letters,” at least in the hands of these two seasoned pros, conquers all—and you’ll be particularly wowed by Farrow, who effortlessly ages 50 years in the play’s 90 minutes, transforming from a playful schoolgirl to a middle-aged woman, unraveling and full of regret.

The tale is a simple one. Melissa Gardner and Andrew Makepeace Ladd III (or, “the turd,” as Melissa calls him in a moment of pique) exchange notes over a half-century, beginning in grade school. Each is a New England WASP, making her and his way down a sometimes-stifling path laid out by their parents: prep school, a European tour, etc.

She’s from a fabulously wealthy family. His folks are just well-off. Fortune will favor Andy over a half-century, but be less kind to Melissa. It is truly their love story, but not always in a traditional sense.

Dennehy and Farrow have chemistry in abundant supply. It surely helps that the venerable actor has read “Love Letters” before, more than two decades ago. So too is it useful that Gurney’s dialogue, sometimes uncannily, can feel as if it was written with the ethereal Farrow in mind: “We’re living in a carriage house in New Canaan close to the train station, and I’ve got a studio all of my own,” art student Melissa says, in one exchange.

The hulking, full-of-presence Dennehy wears a solid blazer, over a blue button-down. Farrow is in a black dress, wearing a necklace with a charm that enhances her delicate qualities. Their rhythms—the hurried back-and-forths in the heat of an argument, the pregnant pauses, when someone’s feelings have been injured—are a testament to strong direction by Gregory Mosher, the longtime Lincoln Center, Broadway and West End helmsman.

Some honesty? Offhand, it wouldn’t have been my first choice to see Farrow as Melissa, given some of the other actresses attached to “Love Letters” later this season (Carol Burnett! Next month!!). But what a performance I would have missed.

I thrilled at Farrow’s relief when Melissa hears from Andy after a prolonged absence. I felt the agony to my bones when Melissa realizes Andy has abandoned her, after enduring a particularly hateful onslaught of language about the “Japanese war bride” he’s taken (do with that what you will, tabloid readers…).

Dennehy, with his gruff mannerisms and scowl, is excellent in a role that is, in ways, the more complex. Andy proves partly responsible for Melissa’s descent—yet the play can only stay on solid ground if Andy is ultimately likable. He pulls it off with authority.

Dennehy and Farrow are simply well-matched. It helps that I’m a fan of Gurney’s particularly lucid and conversational style, also on exhibit now at Signature Center, where the far less well-known “The Wayside Motor Inn” is enjoying a solid staging. The Pulitzer-nominated “Love Letters,” by comparison, is a near-classic.

Clearly, no two pairings will offer the same takeaway. Dennehy will read Andy a month from now opposite Burnett, in what promises to be an entirely different experience. Afterward, Alan Alda teams with Candice Bergen, Stacy Keach appears with Diana Rigg, and Anjelica Huston reads opposite Martin Sheen.

Meanwhile, Dennehy and Farrow do a beautiful job of depicting the volatility and fragility of human relationships.

“Love Letters,” through Feb. 1, 2015 at the Brooks Atkinson Theatre, 256 W. 47th St. Tickets: $52-$127. Call 800-745-3000, or visit Ticketmaster.com.

Follow Robert Kahn on Twitter@RobertKahn